Serena Williams' quest for a record-equalling 24th grand slam title has been delayed again after being overpowered 6-3 6-4 by third seed Naomi Osaka in the Australian Open semi-finals.

Stuck on 23 slam championships since reigning supreme at Melbourne Park in 2017, Williams was hoping to move within a step of matching Margaret Court's record.

But the 39-year-old former world number one was taken down by three-time major champion Osaka in a blockbuster battle of the big hitters on Thursday.

Japanese star Osaka will now face either Jennifer Brady or Karolina Muchova in Saturday's final as she eyes her second Australian Open crown.

Osaka – the youngest player remaining in the draw – initially struggled under the beaming Melbourne sun as fans returned to Rod Laver Arena following a five-day state-wide lockdown after a coronavirus outbreak.

She was in all sorts, struggling on serve and tallying five unforced errors through two forgettable games as Williams raced out to a 2-0 lead.

Osaka – boasting a 3-0 record in grand slam semis – faced a 30-40 deficit and potential 0-3 hole before digging deep to hold for the first time.

It proved to be a turning point for Osaka, who went on a roll by reeling off five successive games and six of the next seven to take complete control.

The tables turned on Williams, who saw her unforced-error count balloon out to 16 while only hitting four winners in the opening set.

Williams – the oldest woman to reach the semis in Melbourne in the Open Era – carried a flawless Australian Open semi-final record into the contest, having won all eight of her previous final-four showdowns.

But Williams cut a frustrated figure at the start of the second set as she yelled at herself "make a shot" amid her demise – Osaka breaking in the first game before consolidating.

However Osaka, who has gone on to win the title each time after advancing past the round of 16 at a slam – 2018 US Open, 2019 Australian Open and 2020 US Open, lost her way when serving at 4-3 as three double faults saw her broken by Williams.

Williams, beaten by Osaka in an infamous US Open final three years ago, regifted the compliment the very next game, Osaka hitting three stunning winners to break to love before sealing her place in the women's decider.

Data slam: Osaka stays hot
She has now won 20 consecutive matches since losing while on Fed Cup duty for Japan last February. A 21st successive victory would yield a fourth slam triumph.

WINNERS/UNFORCED ERRORS
Williams – 12/24
Osaka – 20/21

ACES/DOUBLE FAULTS
Williams – 3/1
Osaka – 6/8

BREAK POINTS WON
Williams – 2/7
Osaka – 4/4

Jennifer Brady believes a two-week hard quarantine upon arriving in Australia helped her make a run to the semi-finals at Melbourne Park.

As one of the 72 Australian Open entrants that had potentially been exposed to COVID-19 on chartered flights to Melbourne, Brady was forced to stay in a hotel room for a fortnight ahead of the first grand slam of the year.

However, the 25-year-old booked her place in the final four on Wednesday by coming from behind to defeat Jessica Pegula 4-6 6-2 6-1 in an hour and 40 minutes on Rod Laver Arena.

While some players voiced their displeasure with the conditions they were faced with in self-isolation, Brady felt the period served her well.

"I was pretty much going non-stop since June of last year. I was playing World TeamTennis, then played tournaments in the US, then went over to Europe and was training in Europe till December," said Brady.

"I didn't have any weeks off. Mentally I was feeling a little bit fried, to be honest. I think I used that two weeks to kind of reset mentally and also physically, just give myself, my mind, my body a little bit of a rest.

"I would say I didn't really have high expectations on myself to do well. I came out of the quarantine, and then we were lucky enough to have a separate tournament for us who were in the hard lockdown. I was lucky to get a couple matches in there before starting here in the Australian Open."

The 22nd seed will take on Karolina Muchova in the last four, the Czech having stunned world number one Ash Barty earlier in the day. In the other half of the draw, Serena Williams will take on Naomi Osaka.

Brady hopes to get an opportunity to challenge herself against 39-year-old veteran Williams, who is chasing a record-equalling 24th major singles title.

"I think just being in the same draw as Serena is obviously... when she retires, if she retires, it's going to be something I'll be extremely grateful for. I hope I get to play her before she retires," said Brady.

"Yeah, I think she's the G.O.A.T. She's the greatest of all time and definitely will be the greatest of all time."

Brady made her first grand slam semi-final appearance at last year's US Open, when Williams and Osaka were also in the final four.

She suffered a three-set loss to Osaka on that occasion, but she is pleased to be performing on a par with the Japanese and Williams.

"I think it says a lot. They're obviously great, great tennis players, champions of the sport. To be categorised in the same group as them, I'll take that as an honour," said Brady.

"I think it's a huge achievement for me to make the semi-finals here. I look to make the finals, so we'll see."

Only Muchova stands between Brady and a first major final and fans will be able to attend after lockdown was lifted in Victoria, with a crowd of 7,477 – approximately 50 per cent capacity – allowed for each session.

Brady said of her next opponent: "She's crafty. She looks to move forward, has an all-court game. She's really athletic.

"I hope it will be a good, competitive match. Yeah, I'm looking forward to it."

Serena Williams admitted it felt like stepping back in time as her movement and power came together to overwhelm Simona Halep at the Australian Open.

It had been just over 18 months since Halep destroyed Williams in the Wimbledon final, and with the American great approaching her 40th birthday, prospects of a 24th grand slam title have appeared to fade.

Into the conversation on Tuesday strolled a revitalised Williams, a woman who has been proving a point and defying expectation for coming up to a quarter of a century.

Williams is simply not having it that her days as a winner might be over, which is why she and coach Patrick Mouratoglou are always seeking marginal gains.

Dogged by an Achilles injury since the US Open last September, Williams feels over that, and a 6-3 6-3 quarter-final win over Halep attested to that being the case.

More than that, though, Williams noticed the years fall away as she dashed around the court, thumping groundstrokes with abundant power and often plenty of precision.

Speaking of the movement returning, Williams said: "It was something that Patrick and I did discuss. I just wasn't able to incorporate it as much as I would have liked to.

"But once I was able to get on the court, I was able to incorporate it as much as I could. Movement has always been one of my strengths, and so it's actually more natural for me to move than for me not. So it was just kind of, like, 'Oh, that's how I used to move', so it's pretty good.

"I'm happy that I'm doing that again and that I put it back into my game. I think I was more focused on other things and not focused on something that is actually a strength of mine, has always been a strength of mine, and I had to refocus on that."

She faces Naomi Osaka next for a place in the final. It reads like a match-up of an all-time great against a player who could over time join her in that pantheon.

Osaka is pursuing a fourth grand slam title, while Williams wants the 24th as much as she craved the first, given it would move her alongside Margaret Court at the top of the all-time list.

The veteran American's most recent slam title came while pregnant in Australia four years ago, with Williams dealt four final defeats since, including a notable one to Osaka at the 2018 US Open.

If Osaka was watching Williams on Tuesday, as she surely was, the Japanese player could have only been impressed.

When asked about how she was matching and often out-matching Halep even in the longest rallies, Williams paused to consider when she was last able to boss such exchanges.

"It's definitely been a minute. It's been a long minute," she said with a smile. "I think 19... 1926, the summer of 1926 I think was the last time I felt that.

"But I'm good at rallying and I have to embrace the things I'm good at. I'm good at playing power, I'm good at hitting a hundred balls.

"That's one thing that's unique about me that I just need to kind of accept and embrace and just be good at both."

Williams and Osaka may have a crowd on Thursday for the semi-final, or they may not. Melbourne remains in lockdown but spectators could be back on Rod Laver Arena for the clash of two of the sport's biggest personalities.

Addressing that prospect, Williams indicated she would have mixed emotions.

"I love having the people there, obviously. But at the same time, it's kind of nice to not have, like ... more pressure when there is people in the stands," Williams said.

"So I think either way it's really a win-win situation. That's kind of how I look at it."

Fast-footed on the court, quick to sidestep off it, Williams is convinced she can push Osaka hard, perhaps heartened by a narrow win when they met in an exhibition match in Adelaide last month.

"I've got to keep going. Obviously I have an incredible opponent to play, so it would be nice to hopefully keep raising the level of my game. I'm going to have to," Williams said.

Halep said Williams "was stronger in the important moments", and she too noticed her opponent showing something near vintage form.

"Yeah, she's moving better and she hits strong," Halep added. "I feel like she's in a good shape now. She has a really good game. Always did..."

Serena Williams is in the Australian Open semi-finals for the first time since she last won a grand slam title, beating Simona Halep to set up a mouthwatering clash with Naomi Osaka.

The American great gained revenge for her Wimbledon final defeat to the Romanian two seasons ago as she conjured a 6-3 6-3 win on Rod Laver Arena.

Halep dropped just four games in that stunning grass-court success in 2019, the third of four grand slam finals that Williams has lost since landing her 23rd major in Australia four years ago.

The 24th title has remained frustratingly elusive, with Williams one away from matching Margaret Court's record haul, but perhaps this is the week where that changes.

She must get past Osaka, her heir apparent as the figurehead for the women's game, but Williams showed her prowess in this match, devastatingly proving a point.

Her power won out, with 24 winners to just nine from Halep, although the 33 unforced errors from Williams showed there is room for improvement in precision.

The tone was set from the first point, Williams with a brilliant forehand service return winner on the forehand side on her way to an immediate break of serve.

Halep forced her way level but Williams raised the tempo in the sixth game and a deep forehand into the Romanian's backhand corner secured a 4-2 advantage.

Williams served out the set to love at the first opportunity but then dipped early in the second set, Halep pinching a break when the American volleyed waywardly at the net.

What proved a consistent theme was Halep's struggle to hit through her opponent, and the two-time grand slam winner could not capitalise on a 3-1 lead in that second set, dropping five successive games as the 39-year-old Williams began to turn on some vintage form.

Dismissive of the often weak Halep serve, Williams swept through to the clash with Osaka.

"I definitely think this was the best match I've played this tournament for sure," Williams said. "I had to, going up against the number two in the world. I knew I had to do better and that's what I did, so I'm excited."

Looking forward to facing Osaka, Williams said in her on-court interview: "She's such a strong player on the court and such an inspirational person off the court, which I think is really cool. I've been watching her and I'm sure she's been watching me."

Former world number one Naomi Osaka is unfazed about her record at grand slams as she eyes consistency after reaching the Australian Open semi-finals.

Osaka will face either 23-time slam champion Serena Williams or Simona Halep in the semis following Tuesday's emphatic 6-2 6-2 win over Hsieh Su-wei in Melbourne.

Three-time major winner Osaka has gone on to win the title each time she has reached the quarter-finals of a slam – beating Hsieh en route to her 2019 Australian Open triumph.

Asked about the record, Osaka told reporters: "I don't really care about the stat. Just because I've only been to four quarter-finals.

"It feels something like 20. That would be cool. But four, it's not really doing too much for me.

"I would be more impressed if I didn't lose in finals. If it says 10-0 in finals. But the fact is if I don't reach the finals, I lose in the fourth round or the third round.

"For me, I'm happy to be more consistent. I think I'm being more consistent since New York, so that's the ultimate goal for me."

Osaka – in the midst of a 19-match winning streak – overpowered veteran Hsieh on Rod Laver Arena, where the Japanese star hit 24 winners and just 14 unforced errors, while she lost just two of her 25 first-service points.

It does not get any easier for Osaka, with record-chasing Williams or two-time slam champion Halep standing in the way of a trip to Saturday's decider at Melbourne Park.

"I played both of them before I think multiple times," Osaka – confident after saving two match points against Garbine Muguruza in the last 16 – said.

"Halep, I don't really like playing her. She's someone that's really tough, someone that gets the ball back every time. For me it's definitely a mental and physical battle.

"Of course, the same goes for Serena. She's Serena, someone that I feel really intimidated when I see her on the other side of the court."

Serena Williams is moving better than she has in years, according to her coach Patrick Mouratoglou.

Williams, 39, has looked in good form at the Australian Open as she eyes a record-equalling 24th grand slam singles title.

The American has dropped just one set on her way to the quarter-finals, in which she faces Simona Halep on Tuesday.

Mouratoglou said Williams' movement was the best it has been in several years.

"First of all, it's something that we have put the emphasis on because in tennis that's probably one of the most important things. If you are late on the ball, you can't do what you want to do. Sometimes you don't even touch the ball," he told a news conference on Monday.

"It's a sport where you have to be able to move fast from side to side and long enough. It's something that probably in the last two, three years, this had consequences for Serena.

"Even more, when you're not in a good day, you need a plan B. To be able to have a plan B, you have to be able to move well. If you can't move well, there is no plan B. The only plan is attack.

"I think it cost her a few important matches. So we have decided to find a way to bring back the footwork that she used to have in the past. I feel like she's done a great job. She's moving much better."

Williams last won a major title in Melbourne in 2017, losing four grand slam finals since then.

With all eyes on her as she aims to equal Margaret Court's record of 24 grand slam singles titles, Mouratoglou insisted that mark was not an obsession for Williams.

"Does she need that validation? I don't think she needs that validation.  But, I mean, clearly she came back to tennis to win some other grand slams, so that's for sure the goal," he said.

"Now, she's not as obsessed with the 24 than most of the people in the tennis world, but definitely she wants to win grand slams. That's the only reason why she came back to tennis."

Simona Halep set up a quarter-final duel with Serena Williams after showing admirable character to battle back from a set down to beat Iga Swiatek 3-6 6-1 6-4 and seal her 100th grand slam match win.

Halep and Swiatek put on a thrilling show in the night session on Sunday, as the Romanian two-time grand slam champion demonstrated her fighting spirit to come from a set down and reach the last eight.

Swiatek took charge in the first set after saving the first two break points of the contest, eventually putting herself in a commanding position as she won the 10 of the final 11 points of the set, but Halep remained focused as her 19-year-old opponent began to wobble in the second.

Halep then snuffed out any threat of a turnaround by breaking back straight after losing on her own service in the decider and she went on to set up a meeting with Williams, who had overpowered Aryna Sabalenka earlier in the day.

Naomi Osaka also advanced, though she was by no means comfortable, while Hsieh Su-wei beat Marketa Vondrousova in straight sets.

HALEP'S REVENGE

Halep's clash with Swiatek was their first since the French Open last October, when Swiatek ran out a 6-1 6-2 winner and went on to claim her maiden major title.

Revenge was on the cards at Melbourne Park and Halep got the job done impressively, showing her mettle to return from a set down.

"Well, I thought before the match that I have to be a little bit more aggressive than Paris. In Paris I have been very far back, and my ball didn't go through the court," the second seed said. "So, I thought that it's a better chance to go and hit.

"The pressure came from the way I played the last match against her. I just expected a better game from myself, which I did, and I'm really happy about that."

Halep accepts facing Williams will be an entirely different challenge, but she remains confident despite lauding the American a "legend" in her on-court interview.

"Of course it's different, she's the only one with 23 grand slams, so you cannot compare Serena with all of us, because we do not have so many grand slams," Halep added.

"But when I step on the court, it's just another opponent, and always I'm focused on myself more than I focus on who I play. We played so many times. I know what to expect. I will just try to do my game, and I will be confident."

WILLIAMS ON COURSE

All eyes are on Williams yet again, as she hopes to equal Margaret Court's record of 24 grand slam titles – and on the evidence of her latest win, she will take some stopping as she won 6-4 2-6 6-4.

Williams revealed she had to cope with a little off-court stress this week with her clothing line, and Sabalenka certainly kept the pressure up as the 22-year-old took the second set.

But Williams responded well to the seventh seed, who became the first player to take a set off the former world number one. Williams said she remained confident despite that setback.

"Like I said on the court, I just felt like even games that I lost, I was so close to winning. Not all games, but probably most of those games," she said. "I just needed to play better on the big points.  I knew that I could. I still hadn't reached my peak. I was like, 'Okay, Serena, you got this, just keep going.'"

OSAKA RELEASES HER ANGER

Osaka was in a real spot of bother against Garbine Muguruza, but saved two match points.

The 2019 champion Osaka steadied herself and felt more composed after a brief show of frustration, as she struck the ground with her racquet.

Ultimately, she emerged a 4-6 6-4 7-5 victor, and Osaka felt letting frustration get the better of her for a moment helped her cause.

"On the first match point, I was just thinking that I didn't hit a decent serve that entire game, so I should really focus on my serve," he said. "I feel like my serve stats were pretty good that set, so I was just telling myself to do better.

"Then on the second point, when the rally started, I just told myself not to push [the ball] but also don't do something crazy and make a really bad unforced error. I felt the entire match I was overthinking. There was a moment when I got angry and hit my racquet on the ground. I feel like I released a lot of the thoughts that I had. It just made me go more into instinct-based tennis."

She will face Hsieh next, the world number 71 having beaten Vondrousova – ranked 51 places higher – 6-4 6-2.

Serena Williams calmed injured fears after coming through a thrilling back-and-forth against Arnya Sabalenka to reach the quarter-finals of the Australian Open.

Williams, who is pursuing a record-equalling 24th career grand slam and her first major victory in four years, prevailed 6-4 2-6 6-4 after more than two hours on court against seventh seed Sabalenka.

Her struggles during the second set appeared partly attributable to a fall but Williams recovered her poise and the 39-year-old does not expect any ill-effects in a last-eight showdown against either Simona Halep or Iga Swiatek.

"I don't think so. It didn't hurt at all. I didn't roll my ankle, so that was good," she told reporters.

"Yeah, I think it was just dramatic, me being dramatic.

"My first thought was, 'Not another ankle sprain in Australia'. But I knew immediately that it wasn't.

"Then I was more embarrassed than anything. I was like, 'Oh, my goodness'."

Williams moved well throughout the contest, assuaging any lingering concerns over Achilles problems that have dogged her of late - even manging to rally when Sabalenka reeled off three consecutive games from 1-4 down in the decider.

"I've worked really hard on my movement. Yeah, I like retrieving balls. I mean, obviously I like to be on the offense, but I can play defence really well, as well.

"I do get a lot of balls back when I need to. I didn't think about my Achilles. It's so good to not think about it. Oh, my goodness. It's been a problem actually since 2018.

"I just never want that problem again. It feels really good to just play and to run, to not feel that. It's a great relief."

Arguably Williams' greatest inconvenience around the match was not a physical one, after she had to participate in a Saturday conference call to avert an "emergency" at her clothing business.

"Tennis is a lot less stressful. I don't have to manage a team. I do manage a team actually, but it's different," she chuckled. "Even though I am the CEO of my tennis team, it's definitely different.

"I think a part of me loves being on the court because it's free-flowing. It's not like I have to kind of just manage and make sure everyone is able to perform.

"I have a second career and it's fun. One of our main players, our employees, had an emergency. You got to step it up when you got to step it up.

"I was smart about that. I scheduled a call directly after my practice. I was like, 'Okay, I can do it early and still have the rest of the day to relax'.

"And it was during [Williams' daughter] Olympia's nap, so it was perfect."

Serena Williams moved a step closer to a record-equalling 24th grand slam title after outlasting Aryna Sabalenka in an absorbing battle to reach the Australian Open quarter-finals.

Williams – in pursuit of Margaret Court's record slam haul of 24 – has not tasted major success since winning the Australian Open in 2017.

But former world number one Williams and her bid to match Court remains on track following Sunday's thrilling 6-4 2-6 6-4 victory over seventh seed Sabalenka after more than two hours.

No fans were allowed to attend Melbourne Park amid a coronavirus lockdown in Victoria, but there was still plenty of noise inside Rod Laver Arena in a battle between two big hitters.

Williams, who reached 90 Australian Open wins in 101 appearances in Melbourne last time out – she has played and won more matches than any other woman in the tournament's history, prevailed in a tense opening set.

After fending off a break point in the seventh game, Williams – moving extremely well against the 22-year-old – was gifted a second break-point chance of her own three games later and she pounced as Sabalenka fired a forehand into the net.

The seven-time Australian Open champion hit 12 winners and just nine unforced errors in a fast and ferocious first set.

Williams owned a career 53-8 record in last-16 matches at grand slams heading into the contest – last falling at this stage when she pulled out ahead of her French Open showdown with Maria Sharapova in 2018, while her last match loss at this stage came in Melbourne in 2014.

But Sabalenka was unperturbed, the Belarusian – eyeing her maiden slam quarter-final – an unstoppable force against a helpless Williams in the second set, breaking in the first, third and fifth game.

Williams, who only made 36 per cent of her first serves, was moved around the court as she dropped a set for the first time at this year's Australian Open.

Having cut a frustrated figure in the second set, Williams emerged with renewed figure in the decider – the 39-year-old claiming the decisive break of serve in the fourth game for a 3-1 lead before digging deep to consolidate.

Sabalenka reeled off three consecutive games to put the match back on serve, but she was unable to maintain her charge against Williams, who closed out the match on her opponents' serve.

Data Slam: Serena steps up on serve
Not much went right for Williams on serve in a lopsided second set. But when it mattered most, the 12th seed stepped up by serving at 71 per cent in the third – winning 17 of 22 first-serve points against Sabalenka.

WINNERS/UNFORCED ERRORS
Williams – 30/26
Sabalenka – 24/36

ACES/DOUBLE FAULTS
Williams – 9/8
Sabalenka – 4/4

BREAK POINTS WON
Williams – 4/9
Sabalenka – 4/11

Naomi Osaka and Garbine Muguruza set up a blockbuster clash at the Australian Open, while Aryna Sabalenka cannot wait to face Serena Williams.

As Williams was tested before winning through, Osaka and Muguruza raced through their third-round outings in Melbourne on Friday.

Osaka and Muguruza dropped just seven games between them to set up what will be their first meeting, which will take place without fans in attendance as Victoria prepares to move into a five-day lockdown beginning on Saturday due to coronavirus concerns.

Sabalenka also progressed and will next face Williams, while Simona Halep cruised through.

OSAKA, MUGURUZA STORM THROUGH

Osaka, the three-time grand slam champion, brushed past fellow seed Ons Jabeur 6-3 6-2 in the third round.

The Japanese star, winner of the Australian Open in 2019, is looking forward to facing fellow major champion Muguruza.

"I've practised with her once, but it was on grass, and I was younger. It was maybe like a couple years ago," Osaka said.

"But I just remember being really impressed by her, and for me, I've watched her win Wimbledon and win the French Open when I was younger, and I've always wanted to have the chance to play her. So for me, this is really exciting."

A finalist at the Yarra Valley Classic last week, Muguruza's strong start to the Australian Open continued with a 6-1 6-1 thrashing of Zarina Diyas.

"I don't think we've played each other before. Just looking forward for a fourth round, a good fourth round, playing the top players," Muguruza – who has lost just 10 games in the first three rounds – said ahead of facing Osaka. "I feel like that's always the right way, you know, a good sign. Just expecting a good match."

JOB DONE FOR SERENA

Williams' bid for a record-equalling 24th grand slam singles title remains on track after overcoming Russian teenager Anastasia Potapova 7-6 (7-5) 6-2.

In her 101st Australian Open match, Williams secured her 90th career victory in Melbourne. The 39-year-old also improved her overall slam record to 360-51 – Martina Navratilova (306-49) is the only other player to pass 300 wins in the Open Era.

Next up for Williams is Sabalenka, who was too good for Ann Li, winning 6-3 6-1 to reach a major fourth round for just the second time in her career and first in Melbourne.

The Belarusian seventh seed is not daunted by the task facing her when she meets the American for the first time.

"I want to get this thrill. Can I say thrill? I said it right. So it's going to be a thrill. But, yeah. I'm going to do everything I can," Sabalenka said.

HALEP THROUGH AS SEEDS CRUISE

Halep reached the fourth round in Melbourne for the sixth time with a convincing 6-1 6-3 win over Russian 32nd seed Veronika Kudermetova.

Awaiting the two-time major winner in the fourth round is Iga Swiatek after the Polish 15th seed got past Fiona Ferro 6-4 6-3.

Swiatek thrashed Halep 6-1 6-2 on her way to the French Open title last year.

Marketa Vondrousova, the 2019 French Open runner-up, reached the fourth round of the Australian Open for the first time after beating Sorana Cirstea 6-2 6-4.

Up next for the Czech 19th seed is Hsieh Su-wei, who battled past Sara Errani 6-4 2-6 7-5 after two hours and 44 minutes.

Errani had won her previous three meetings with Hsieh in straight sets, including winning a set 6-0 - known as a 'bagel' in tennis parlance - in each of those victories.

It meant Hsieh, 35, had a simple plan against the Italian.

"I don't remember when I lose to someone but someone reminded me I eat the bagel every time so I said, 'Okay, I will try to not take any bagel today'," she said.

Serena Williams labelled Victoria's five-day lockdown "rough" as the Australian Open prepares to go behind closed doors amid the coronavirus pandemic.

Fans will not be allowed to attend Melbourne Park - where crowds have been capped at 30,000 per day - from 11:59pm (local time) on Friday until Wednesday after the Victorian government announced a new state-wide lockdown to control an outbreak of the UK COVID-19 strain.

Victorian premier Daniel Andrews made the announcement as Williams booked her spot in the fourth round of the Australian Open, where the 23-time grand slam champion overcame Anastasia Potapova 7-6 (7-5) 6-2.

"I didn't know at all until the match was over. I think it's good that I didn't know," seven-time Australian Open champion Williams told reporters when asked about the lockdown.

"It's rough. It's going to be a rough few days for I think everyone. But we'll hopefully get through it."

American superstar Williams added: "It's not ideal. It's been really fun to have the crowd back, especially here. It's been really cool.

"But, you know what, at the end of the day we have to do what's best. Hopefully it will be all right."

Williams - stuck on 23 majors since winning the 2017 Australian Open in pursuit of Margaret Court's all-time record of 24 - was pushed to the limit by Russian teenager Potapova but prevailed on Rod Laver Arena.

The 39-year-old Williams - who has played and won more matches than any other woman in the tournament's history - celebrated her 90th Australian Open victory in her 101st contest.

"It was good to get through that match," said former world number one Williams as seventh seed Aryna Sabalenka awaits in the last 16. "The first set was extremely tight. I was a little tight, but it worked out. Was able to play a little more free in the second set."

Serena Williams remains on track to claim a record-equalling 24th grand slam title after overcoming Anastasia Potapova in a hard-fought battle en route to the Australian Open last 16. 

Williams - stuck on 23 majors since winning the 2017 Australian Open in pursuit of Margaret Court's all-time record - was pushed to the limit by Russian teenager Potapova but prevailed 7-6 (7-5) 6-2 in Melbourne on Friday.

Next up for seven-time Australian Open winner Williams is seventh seed Aryna Sabalenka.

Williams - who has played and won more matches than any other woman in the tournament's history - had only lost four times at a slam to a player ranked outside the top 50 and twice to players outside the top 100.

But she was challenged by Potapova in an error-riddled and difficult opening set on Rod Laver Arena, where the unheralded Russian took the match to her superstar opponent.

Williams hit 22 unforced errors to just 12 winners, faced 11 break points as she was broken twice, and saved a pair of set points en route to a tense tie-break.

Maintaining her challenge, Potapova led 4-2 and 5-3 in the tie-break, but Williams was up to the task - closing out the set in 61 minutes.

Potapova, who only broke the American's serve on one occasion in last year's opening-round loss at Melbourne Park, was not deflated following the tie-break and broke Williams in the first game of the second set.

But like the first set, Potapova was unable to hold serve and Williams took full advantage - breaking twice to secure a 16th fourth-round berth in Melbourne.

Data Slam: Williams rolls on in Melbourne
In her 101st Australian Open match, Williams secured her 90th career victory in Melbourne. The 39-year-old also improved her overall slam record to 360-51 - Martina Navratilova (306-49) is the only other player to pass 300 wins in the Open Era.
 

WINNERS/UNFORCED ERRORS
Williams – 19/31
Potapova – 18/28

ACES/DOUBLE FAULTS
Williams – 9/4
Potapova – 2/8

BREAK POINTS WON
Williams – 5/8
Potapova – 3/12

Serena Williams and Naomi Osaka sizzled in the scorching Melbourne heat on day three of the Australian Open. 

Williams, aiming once more for a record-equalling 24th singles grand slam, made serene progress from round two on what was the hottest day of the tournament so far. 

It was a similar story for Osaka, who is aiming to become a two-time champion at Melbourne Park, but Simona Halep had to dig deep while Bianca Andreescu and Petra Kvitova were early casualties on Wednesday.

PLAIN SAILING FOR SERENA AND OSAKA

Williams' perfect start to the season extended to 5-0 as she swatted aside Nina Stojanovic 6-3 6-0 to set up a round-three meeting with Anastasia Potapova – the same opponent she overcame in Melbourne in the first round a year ago. 

The seven-time Australian Open champion is looking forward to renewing acquaintances with the Russian. 

"It's always a fun, interesting match [against Potapova]. I'm gonna go home, get ready and just do the best," she said.  

"We're all out here to have fun and I'm happy to be out here, and just to be playing in front of crowd again is really cool. So every day is just fun." 

Osaka, the current US Open champion and the winner in Melbourne two years ago, hammered former world number four Caroline Garcia 6-2 6-3 on Rod Laver Arena in the evening session. 

The Japanese star is set to face her friend Ons Jabeur for the first time in an official match in round three. 

"She's really funny," Osaka said of her next opponent. "I don't know if you guys watch any of her interviews. I think she is really funny and nice.  

"I think the match I am going to play against her will be really difficult, but I'm looking forward to it." 

HALEP SURVIVES TOMLJANOVIC TEST

In contrast to Williams and Osaka's comfortable wins, second seed Halep was taken to the brink by home favourite Ajla Tomljanovic, who won the first set and was serving for the match in the third. 

However, 2018 finalist Halep broke back when trailing 5-4 in the decider and battled through with a 4-6 6-4 7-5 victory in a match that saw a combined 94 unforced errors (57 for Tomljanovic, 37 for Halep). 

"I was expecting that she would play very hard and very strong. I expected it to be a difficult match, but it was more than I thought. But I'm really happy that I can smile now," Halep said.  

"I was not that positive when I was talking to myself. I didn't talk about the score, I was just blaming myself, that I'm not strong enough to win against her. But in the end mentally I was maybe a bit stronger than her, and I didn't want to give up." 

Last year's losing finalist Garbine Muguruza (14) was too good for Ludmilla Samsonova in a 6-3 6-1 win, while French Open champion Iga Swiatek (15) dispatched Camila Giorgi 6-2 6-4. 

Aryna Sabalenka (7), Marketa Vondrousova (19) and Veronika Kudermetova (32) all made it through, but fellow seed Elena Rybakina (17) was beaten in straight sets by Fiona Ferro.

EARLY EXITS FOR ANDREESCU AND KVITOVA

Andreescu became the latest scalp for veteran Hsieh Su-Wei, who earned a commanding 6-3 6-2 victory and is now 4-3 against top-10 players in the slams since 2017. 

Eighth seed Andreescu won the US Open in 2019 but missed the entirety of last year with a knee injury, while her preparation here was disrupted by spending 14 days in quarantine after her coach tested positive for coronavirus. 

"After my first round, I thought I would feel more exhausted, but I felt amazing. Also, today the weather was a bit tricky. Being in the heart of quarantine I could have had those extra two weeks of like being in the heat and getting used to sweating and all of that," she said. 

Next up for Hsieh is Sara Errani, who defeated Venus Williams 6-1 6-0. The veteran American rolled her ankle towards the end of the first set and, despite needing two medical timeouts, valiantly saw out the match. 

Kvitova was a runner-up to Osaka in 2019 and appeared on course to recovery after dominating the second set against Sorana Cirstea. 

But amid sweltering conditions, the Czech ninth seed went on to lose the decider. 

"It was quite a rollercoaster, for sure," she said. "Unfortunately I couldn't take the chances to win the first set.  

"I think that was really the key of the match. She really had a great day today; she played a good game. I didn't really bring the best tennis today. It's really hurting."

Serena Williams is embracing the absence of line judges at this year's Australian Open as the record-chasing American superstar dubbed herself a "futurist, like Iron Man" after reaching the third round. 

The Australian Open is taking place without linespeople as a response to coronavirus restrictions at Melbourne Park, where "Hawk-Eye Live" technology is being used on every court. 

It is the first grand slam to replace all line judges with technology as the tournament seeks to limit the number of people on court amid the COVID-19 pandemic.

After easing past Nina Stojanovic 6-3 6-0 on Wednesday, 23-time grand slam champion and seven-time Australian Open winner Williams welcomed the use of technology.

"I like it," Williams, who is looking to equal Margaret Court's record of 24 slams, told reporters when asked about the technology post-match. "I didn't like it in Cincinnati because they had that in Cincinnati and I was, it was different. It was weird. 

"I like it now because it takes away a lot of the human error, which clearly I definitely don't need. I should be the biggest fan of that. 

"But I feel like sometimes I definitely still want to see that ball, but I'm like, okay, even if I see it, the computer's going to show me what the computer just said. So that's kind of how I think about it. 

"I'm a futurist, like Iron Man, so I definitely love technology and it's something that I invest in and so, yeah, I really think is right up my alley."

Williams owns a 359-51 grand slam record in her illustrious career – the only other player to pass 300 victories in the Open Era is Martina Navratilova (306-49).

The 39-year-old Williams is bidding to win her 11th major crown since turning 30.

Only Court (three), Navratilova (three), Chris Evert (two), Billie Jean King (two), Ann Jones (one), Angelique Kerber (one), Li Na (one), Flavia Pennetta (one) and Virginia Wade (one) have won grand slam silverware in their 30s.

Serena Williams booked her spot in the Australian Open third round with a straight-sets win over Nina Stojanovic on Wednesday.

Williams again looked in fine form on her way to a 6-3 6-0 victory over Stojanovic in warm conditions on Rod Laver Arena.

The American star is bidding to equal Margaret Court's record of 24 grand slam singles titles and is on track after her win in one hour, nine minutes.

As her serve gradually improved, Williams – who is dealing with a right shoulder injury – was in control for the most part to set up a third-round clash against Anastasia Potapova.

Stojanovic held her own early, but Williams broke for 3-1, a powerful forehand setting up break point before a backhand error from the Serbian.

Williams was struggling with her first serve – she had a first-serve percentage of just 52 in the first set – but dug herself out of a 15-40 hole to hold for 5-2 on her way to taking the opening set.

A break to begin the second set followed as Stojanovic powered a forehand down the line wide, and three consecutive backhand errors saw her cough up another break to fall 3-0 behind.

Williams took complete control from then on, finishing the second set without an unforced error and losing just nine points to quickly wrap up victory.

Data Slam: Williams' second-round dominance continues
Williams improved her record in the second round of majors to 73-2. It also stands at 19-1 at the Australian Open, where she last failed to reach the third round on her debut main-draw appearance in 1998.

WINNERS/UNFORCED ERRORS
Williams – 27/11
Stojanovic – 15/18

ACES/DOUBLE FAULTS
Williams – 6/1
Stojanovic – 1/4

BREAK POINTS WON
Williams – 4/9
Stojanovic – 0/3