Defending Australian Open champion Naomi Osaka squandered two match points as she suffered a shock third-round exit at the hands of unseeded Amanda Anisimova on Friday.

Osaka eased past Camila Osorio and Madison Brengle in straight sets in the first two rounds but fell to a 4-6 6-3 7-6 (10-5) loss to Anisimova in a thrilling contest.

Anisimova, who won her second career title at Melbourne Summer Set 2 earlier this month and is now 8-0 for the season, will face top seed Ash Barty in the last 16.

Two-time Australian Open winner Osaka had won 24 of her past 25 matches in Melbourne and made a fast start against Anisimova by breaking her opponent in the first game.

She held serve to ease ahead on Margaret Court Arena, but Anisimova battled back well in the second set.

The world number 60 broke Osaka in the fourth game with a sublime disguised backhand drop and served out the set in a relatively straightforward manner.

Anisimova continued to dig in and saved two match points in the 10th game to help pave the way for a decisive first-to-10 tie-break.

Osaka had no response to her opponent's accurate hitting as she fell 3-0 behind and, while she did bring it back to 3-2 and 5-4, Anisimova took five of the next six points to advance in a big upset.

DATA SLAM: Osaka outgunned by Anisimova

Osaka had dropped just one set in her first five matches this season and looked in the mood as she raced ahead against Anisimova.

But the American youngster fired in 11 aces and hit more than twice the number of winners that Osaka managed (46 to 21) to pull off the victory.

With this defeat, Osaka has now failed to defend any of her four major crowns, with Victoria Azarenka the last women's player to do so at Melbourne Park in 2012 and 2013.

WINNERS/UNFORCED ERRORS
Anisimova – 46/44
Osaka – 21/45

ACES/DOUBLE FAULTS
Anisimova – 11/8
Osaka – 5/3

BREAK POINTS WON
Anisimova – 1/8
Osaka – 1/10

Defending Australian Open champion Naomi Osaka squandered two match points as she suffered a shock third-round exit at the hands of unseeded Amanda Anisimova on Friday.

Osaka eased past Camila Osorio and Madison Brengle in straight sets in the first two rounds but fell to a 4-6 6-3 7-6 (10-5) loss to Anisimova in a thrilling contest.

Anisimova, who won her second career title at Melbourne Summer Set 2 earlier this month and is now 8-0 for the season, will face top seed Ash Barty in the last 16.

Two-time Australian Open winner Osaka had won 24 of her past 25 matches in Melbourne and made a fast start against Anisimova by breaking her opponent in the first game.

She held serve to ease ahead on Margaret Court Arena, but Anisimova battled back well in the second set.

The world number 60 broke Osaka in the fourth game with a sublime disguised backhand drop and served out the set in a relatively straightforward manner.

Anisimova continued to dig in and saved two match points in the 10th game to help pave the way for a decisive first-to-10 tie-break.

Osaka had no response to her opponent's accurate hitting as she fell 3-0 behind and, while she did bring it back to 3-2 and 5-4, Anisimova took five of the next six points to advance in a big upset.

Naomi Osaka will face Amanda Anisimova in round three of the Australian Open after easing past Madison Brengle on Wednesday.

The two-time champion in Melbourne won 6-0 6-4 to set up a meeting with the 20-year-old American, who earlier upset Olympic gold medallist Belinda Bencic in straight sets.

Despite a second-set wobble on serve that gave Brengle hope of a comeback, Osaka looked in comfortable control of the contest and has now dropped just one set in her five matches in 2022.

Brengle was a 6-2 6-2 winner in the only previous meeting in Rock Hill way back in 2013, when Osaka had just turned 16 and had barely any Tour experience. Against the Osaka of 2022, a four-time major champion, she had few answers.

Osaka tore through Brengle's defence in the opening set, wrapping it up in 20 minutes while dropping just three points on serve.

Brengle was credited with just one winner in her chaotic first-round match with Dayana Yastremska, who retired trailing 6-1 0-6 0-5. It was not until the second game of the second set that Brengle matched that tally, but it was worth the wait: a brutal inside-out backhand across court, celebrated with gusto, as she began to make inroads on the Osaka serve.

Osaka dug deep, saving three break points before holding for 2-1 and then another with a timely ace in her next service game. Her play was becoming erratic, though, and after saving a further three break points at 3-3, a wild overhead handed Brengle the breakthrough.

Yet if the 31-year-old thought then that the match was just getting started, it was suddenly over. Osaka broke back immediately with a backhand volley at the net and did not lose another point from there, clinching the contest when Brengle's passing shot dropped wide.

DATA SLAM: Osaka into overdrive

Brengle quadrupled her winner count from her first-round match, but the world number 54 was simply outgunned by Osaka when it came to rallies.

The Japanese star fired in 37 winners to 32 unforced errors, turning on the power just when it seemed like the contest was balancing out.

WINNERS/UNFORCED ERRORS
Brengle – 4/14
Osaka – 37/32

ACES/DOUBLE FAULTS
Brengle – 0/1
Osaka – 8/1

BREAK POINTS WON
Brengle – 1/10
Osaka – 5/7

Naomi Osaka insisted she was unaffected by the saga surrounding Novak Djokovic ahead of the Australian Open.

Osaka opened her title defence at Melbourne Park with a 6-3 6-3 win over Colombian Camila Osorio on Monday.

The lead up to the year's first grand slam was overshadowed by the visa saga around Djokovic, who was deported from Australia on Sunday.

But Osaka, a four-time major winner, said the Serbian world number one's situation had no impact on her.

"I mean, to be completely honest, it didn't really affect me. I saw that it affected the men's draw a little bit so you might have to ask a men's player," she said.

"For me, my goal even before this whole situation is to just focus on myself more, what I need to do to become better.

"I wasn't really, I guess, looking at the news too often."

Osaka was unwilling to be drawn on whether Djokovic, whose visa was cancelled by immigration minister Alex Hawke, should be competing in the tournament.

A two-time champion in Melbourne, Osaka said her focus was on herself – with a second-round clash against Madison Brengle awaiting her.

"I feel like people focus on whatever they want to focus on. It's more like an individual question," Osaka said.

"Me, I'm a tennis player. I'll focus on my matches. You, as I guess an audience, focus on whatever is in the news, no?"

Naomi Osaka moved into the Australian Open second round with a straight-sets victory over Camila Osorio on Monday.

The defending champion was largely untroubled by 20-year-old Colombian Osorio, easing to a 6-3 6-3 victory in 68 minutes on Rod Laver Arena.

Osaka, a four-time grand slam winner, has now won 23 of her past 24 matches in Melbourne.

It means a fourth-round showdown between Osaka and world number one Ash Barty remains on the cards.

Osaka made an imperious start and raced into a 5-0 lead after 16 minutes, on the back of eight winners, plus seven unforced errors from Osorio.

Incredibly, Osorio – who was growing in belief – had chances to get back on serve when Osaka was trying to close out the set, but the two-time champion in Melbourne managed to seal it 6-3.

The energetic Osorio was encouraging herself throughout while matching Osaka, who broke for a 2-1 lead in the second set.

In the end, Osaka proved too good despite a decent first-round test, moving into a meeting with either Dayana Yastremska or Madison Brengle.

DATA SLAM: Osaka's first-round record remains strong

Osaka is rarely troubled in the opening round of grand slams. The star is now 19-2 in the first round at majors.

Another challenge awaits. Osaka has never defended any of her major crowns and the last player to defend the women's title at Melbourne Park was Victoria Azarenka (2012 and 2013).

WINNERS/UNFORCED ERRORS
Osaka – 19/28
Osorio – 5/15

ACES/DOUBLE FAULTS
Osaka – 4/3
Osorio – 1/4

BREAK POINTS WON
Osaka – 4/6
Osorio – 1/5

The tennis season has begun with Rafael Nadal, Ash Barty, Paula Badosa and Thanasi Kokkinakis among the champions at small-scale events in Australia.

Yet there has been one dominant story in the sport and little else has had a look-in in the lead-up to the Australian Open.

Now that Novak Djokovic knows his fate, there is the welcome prospect of eyes turning to matters on the tennis court, rather than the Federal Court.

With the action getting under way in Melbourne on Monday, Stats Perform looks at the main protagonists and what the numbers tell us about another high-stakes grand slam.

Djokovic absence blows open men's draw

As defending champion Djokovic heads for home, it is worth a reminder of how he has dominated this tournament.

Nine of his grand slam titles have come in Melbourne, and he has taken the trophy in each of the last three years, helping him cosy up alongside Roger Federer and Rafael Nadal on 20 majors, an all-time record they share. Of the 'Big Three', only Nadal is in the draw this year, with Federer currently on the injured list.

Djokovic has the highest win percentage in the Open Era (since 1969) at the Australian Open, among players with 20 or more wins (91.1 per cent – W82 L8). He was hoping to join Nadal (13 French Opens) and Margaret Court (11 Australian Opens) in the exclusive club of players to reach double figures for singles titles at one slam.

The Serb was also aspiring to become the first man in the Open Era to win four consecutive Australian Opens. It happened once before the tour turned professional, with Roy Emerson winning five in a row from 1963 to 1967. Djokovic has left Melbourne with the title every time that he has made it through to the semi-finals.

So who takes the title now?

Only Bjorn Borg (89.2 per cent) has a higher winning percentage in grand slam matches than Nadal (87.7 per cent) and Djokovic (87.5 per cent) in the Open Era, among players with 100 or more wins. So why not Nadal?

The 35-year-old and Djokovic have carved up 12 of the last 14 grand slam titles, Nadal winning four of those (three French Opens, one US Open). He is battling back from a foot injury lay-off and coronavirus, and might need to get the early rounds out of the way without undue stress to stand a chance at the business end.

The two exceptions in the Nadal-Djokovic sequence of slam dominance have come at the US Open, with Dominic Thiem winning in New York in 2020 and Daniil Medvedev triumphing at Djokovic's expense in last year's Flushing Meadows final. Thiem is not in Australia, but world number two Medvedev is, looking to become the third Russian man to win two slams, after Yevgeny Kafelnikov and Marat Safin.

The last man other than Federer, Nadal and Djokovic to secure back-to-back slam singles title was Andre Agassi (US Open 1999 and Australian Open 2000), but that is Medvedev's objective now, and he has the game to pull it off.

Nadal has reached at least the quarter-final stage in 15 of his last 16 grand slam appearances, winning six of those majors (four French Opens and two US Opens), so he may well be a factor.

Who else is in the frame? Alexander Zverev probably, having reached the quarter-finals in Australia in the last two seasons (SF in 2020 and QF in 2021). He won the Olympic Games and ATP Finals titles last year, so a grand slam is an obvious next step. He might want to keep double faults in check though, having served a tour-high 113 in slams last season.

Stefanos Tsitsipas reached the Australian semi-finals in 2019 and 2021, so throw him into the mix too, and Matteo Berrettini might be a threat. The Italian, a runner-up to Djokovic at Wimbledon in July, served more aces than any other player in grand slams last year (311 aces, 16.4 on average per match).

Others have more modest ambitions

Andy Murray is back at the Australian Open for the first time since 2019, when he lost in the first round against Roberto Bautista Agut in five sets and was more or less given his last rites as a tennis pro after the match, having indicated he was close to retirement.

The five-time Australian Open runner-up last won a match in this tournament in 2017, when he reached round four. A tough opener against Nikoloz Basilashvili awaits.

Spanish 40-year-old Feliciano Lopez will make his 80th appearance in a grand slam and become the second man in the Open Era with 80 or more appearances at the four majors, after Federer (81).

Do not expect an Australian to be men's champion, by the way. The last time an Australian reached the men's singles final was 2005, when Lleyton Hewitt lost against Safin, and the last home champion was Mark Edmondson in 1976.

Barty backed in stacked women's draw

For the first time since 1997, neither Serena nor Venus Williams will take part in the Australian Open. Yet the women's tour is in rude health, even without those great bastions.

Ash Barty is world number one and a standout pick for many, only enhancing her claims after winning an Adelaide International title in the run-up to this fortnight.

But there is staggering depth on the women's side at present, and Barty will face stiff competition.

Incredibly, the last five grand slam finals have featured 10 different women, and teenager Emma Raducanu's against-all-odds US Open triumph in September shows best of all that new stars are emerging.

Yet since 2000, only three non-seeded players have reached the women's singles final at the Australian Open: Serena Williams in 2007, Justine Henin in 2010 and Garbine Muguruza in 2020. 

Barty could become the first Australian to be women's champion since Chris O'Neil in 1978, and the first to reach the final since Wendy Turnbull lost to Hana Mandlikova in 1980.

The Queenslander is the top seed, and the last time the number one failed to reach at least the fourth round at Melbourne Park was in 1979, when Virginia Ruzici lost her opening match. Barty ended a long wait for an Australian winner of the women's title at Wimbledon last year, so why not closer to home as well?

Naomi Osaka is back, so what should we expect?

Truth be told, that's hard to know. Osaka took time out from tennis after the US Open to focus on her mental health and enjoyed hanging out with friends, before deciding she missed tennis enough to go back on tour.

She had three wins at the Melbourne Summer Set tournament recently before withdrawing from a fourth match, saying her body had "got a shock" from the intensity. As defending champion in the season's first major, she has a target on her back and will need to find a way to handle that.

Over the past six seasons, only Osaka has managed to win back-to-back grand slam singles titles among the women, and she has done so twice (US Open 2018 and Australian Open 2019, plus US Open 2020 and Australian Open 2021).

The last player to win back-to-back women's Australian Open singles titles was Victoria Azarenka (2012 and 2013), so it does not happen regularly.

Osaka has an 85 per cent win rate at this tournament: since 2000, only Jennifer Capriati (90 per cent) and Serena Williams (89 per cent) have had a higher win percentage in the main draw.

You want challengers to the big two? Try sticking a pin in the draw

The Daphne Akhurst Memorial Cup, which goes to the champion, is a trophy that upwards of a dozen women will seriously believe they can win.

Aryna Sabalenka has reached the semi-finals of the last two slams but is mired in some kind of hellish serving groove, having made 74 double faults in her last four matches and lost the last three in a row.

Anett Kontaveit won a tour-high 39 matches on hard courts last year but has only been to one grand slam quarter-final – last year in Australia, losing to Simona Halep.

What about Ons Jabeur, who matched Kontaveit for a tour-high 48 wins across all surfaces last year? The Tunisian is queen of the drop shot, making 147 successful such plays on tour last year, more than any other player, and recently reached the top 10 in the WTA rankings for the first time.

Maria Sakkari reached two slam semi-finals last year, the first of her career, and the form of Barbora Krejcikova and Badosa in the past week in Melbourne marks them out as contenders. Both are recent fast-risers, Krejcikova already with a French Open title to show.

WTA Finals champion Muguruza could be the second Spaniard to twice reach the Melbourne title match, after Arantxa Sanchez Vicario (1994 v Steffi Graf and 1995 v Mary Pierce). Spain has never had an Australian Open women's singles winner: former French Open and Wimbledon champ Muguruza is an authentic contender.

Halep was runner-up to Caroline Wozniacki in 2018, a semi-finalist in 2020 and quarter-finalist last year, and a Melbourne Summer Set title was a handy warm-up for the Romanian. Consider her, too.

Monica Seles, in 1991, was the last player to triumph on her debut in the main draw, but she was already a grand slam winner (1990 French Open). Given the strength of the line-up, the prospect of a bolter coming through this field is unlikely, even if the example of Raducanu tells us anything is possible.

Novak Djokovic has been drawn against Miomir Kecmanovic in the opening round of the Australian Open as the defending champion awaits to hear if he can stay in the country.

World number one Djokovic was last week given a medical exemption to enter Australia, despite not being vaccinated, only for border officials to block it upon his arrival.

The 20-time grand slam winner was detained for four days while waiting to appeal the case on Monday, which went in his favour at Melbourne Circuit Court.

Djokovic has since started training ahead of the Australian Open, which begins next Monday, though immigration minister Alex Hawke may yet cancel his visa for a second time. 

A decision on whether Djokovic can compete in the first grand slam of the year, which he has won a record nine times, could be made on Thursday.

Should he be given the all clear to take part, Djokovic will face compatriot Kecmanovic in the first round at Melbourne Park.

Thursday's draw, which was delayed by one hour and 15 minutes for unspecified reasons, also saw fellow 20-time grand slam winner Rafael Nadal paired with Marcos Giron.

Nadal is in the same half of the draw as Djokovic, meaning the pair could meet in the semi-finals, while third seed Alexander Zverev is also in the top half.

Second seed and 2021 finalist Daniil Medvedev is in the bottom half along with Stefanos Tsitsipas and will take on Henri Laaksonen first up.

In the women's draw, Australia's world number one Ash Barty will begin her quest for glory on home soil against a qualifier.

The top seed is on a collision course with defending champion Naomi Osaka, who goes face-to-face with Camila Osorio in round one on her return from a four-month break.

Reigning US Open winner Emma Raducanu is up against Sloane Stephens, who won the New York major in 2017, while Storm Sanders awaits second seed Aryna Sabalenka.

Naomi Osaka will be hoping to be fit for the Australian Open after the reigning champion withdrew from the Melbourne Summer Set 1.

Osaka, who won the most recent of her four grand slam titles last year at Melbourne Park, has looked in fine form this week in her first appearances since returning from the break she took from tennis last year.

The top seed beat Alize Cornet, Maryna Zanevska and Andrea Petkovic en route to the semi-finals, but could not compete against Veronika Kudermetova on Saturday, citing an abdominal injury.

Osaka explained that her body had taken a hit from playing such intense matches in consecutive days, and she instead is looking to rest and recover ahead of the first grand slam of the season, which starts on January 17.

"Sad to withdraw due to injury from my match today, my body got a shock from playing back to back intense matches after the break I took," Osaka tweeted.

"Thank you for all the love this past week [Red heart] I’ll try to rest up and I’ll see you soon!"

Osaka's injury has prevented what looked to be an enticing showdown with Simona Halep, who guaranteed a place in a WTA Tour singles final for a 13th successive season by beating Chinese teenager Zheng Qinwen 6-3 6-2.

Halep's first final came in 2010 and she has taken just a week to get back into her stride after an injury-ravaged 2021 season.

The Romanian, a two-time grand slam champion, went into the week ranked at world number 20, her lowest position at the start of a season since 2013.

However, she has now reached at least the semi-final stage in three successive tournaments, and she will fancy her chances against third seed Kudermetova, who is into her third singles final.

Ash Barty set a new personal best for aces in a match as she rifled 17 past Sofia Kenin on the way through to the Adelaide International 1 semi-finals.

Reigning Wimbledon champion Barty won 31 of 32 points on first serve in a ruthless 6-3 6-4 victory over the 2020 Australian Open winner.

It sets up a tantalising last-four clash with Poland's defending champion Iga Swiatek, who is a frequent practice partner for Australian home favourite Barty.

Explaining her stunning serving performance, Barty said: "I think towards the end Sofia was kind of leaning one way or the other, and I was able to kind of get up and hit my spots."

Facing former French Open winner Swiatek will be a major early-season test for the world number one, with the Warsaw-born 20-year-old fending off former grand slam winner Victoria Azarenka 6-3 2-6 6-1 in Friday's quarter-final.

The other semi-final in Adelaide will see Misaki Doi take on Elena Rybakina after both won in three sets to get there, seeing off Kaja Juvan and Shelby Rogers respectively.

Melbourne Park is staging two tournaments this week, and there is the prospect of a starry final in Melbourne Summer Set 1, with Naomi Osaka and Simona Halep both through to the last four.

Top seed Osaka beat experienced German Andrea Petkovic 6-1 7-5, while second seed Halep had to scrap for a 6-2 5-7 6-4 win against Viktorija Golubic of Switzerland.

Osaka took inspiration from Petkovic's fight in the second set of their contest. Quoted on the tournament website, she said: "It was really cool how she didn't give up for any point, so I just felt like I should do the same thing and see what happens."

Halep said her encounter with Golubic had been "really difficult", adding: "I didn't really trust that I can win this match, but I fought to the end, and I'm very proud of this."

Saturday's semi-finals of Melbourne Summer Set 2 will seed Daria Kasatkina take on Amanda Anisimova, while Ann Li plays Aliaksandra Sasnovich.

Naomi Osaka marked her return to tennis with a hard-fought win in Melbourne and declared her love for competing had been reignited during a break from the sport.

The former world number one beat French player Alize Cornet 6-4 3-6 6-3 on Tuesday, in her first match since a third-round US Open defeat to eventual runner-up Leylah Fernandez.

The Japanese star said after that Flushing Meadows loss in September that she would put her tennis career on hold indefinitely.

Across several months, Osaka has adjusted her personal and professional priorities, pointing to the joy of San Francisco sleepovers with friends and reconnecting with normal life.

She believes there is a way to focus on the joy of competing, rather than the strains of performing in the public eye that caused her so much consternation last season, and there were glimpses of Osaka's best in the win over world number 61 Cornet at the WTA 250 Melbourne Summer Set 1 tournament.

Osaka pulled out of the 2021 French Open after one match and then elected not to play Wimbledon, as she addressed the importance of protecting her mental health.

She was reluctant to take part in media conferences, finding them harrowing at times, but on Tuesday the 24-year-old embraced the stage and explained how she had surprised herself by coming back to the court so soon.

"I actually really thought I wasn't going to play for most of this year," Osaka said. "I'm really happy with myself that I love the sport that much because I literally said that I was unsure when I was going to play after the US Open and I'm here right now.

"In the break I was feeling like I didn't know what my future was going to be. I'm pretty sure a lot of people can relate to that. Of course, you never know what the future holds, but it was definitely an indecisive time. But I'm really happy to be sitting here right now."

Osaka had envisaged a spell of globe-trotting – without a tennis racquet in her luggage – but the pandemic left her wary of following that route.

In the end, she settled on enjoying a quiet life for a while, saying: "I kind of stayed at home. My friends live near San Francisco, so I was driving to go see them and stay over at their house and bother them quite a few times.

"I feel like that's also an experience that I haven't been able to have in my life, just based on the fact that I play tennis and I travel a lot and I haven't been able to have sleepovers and stuff like that. It was cool to be able to do that."

Osaka said she has just "one major goal for 2022".

"For me, I just want to feel like every time I step on the court I'm having fun," she said. "I can walk off the court knowing that even if I lost, I tried as hard as I could. Also, I have a goal in the press room, that I'm never going to cry again, so hopefully that works out in my favour.

"I'm the type of person that cared a little bit too much about the results and the ranking and stuff like that, and I just need to find a way to enjoy the game again. Because that's the reason why I was playing in the first place."

Quoted on the WTA website, Osaka said opening up to others about the tribulations of life on the circuit helped her to adjust her goals.

"During the off-season I just hung out with my friends and talked to my family a lot. I felt like that was a way of decompressing the pressure I had on myself. Then I just slowly started to regain the feeling of love that I had towards the game," she said. "It's not like it ever completely went away, but I felt like it got overshadowed by a lot of emotions that I was feeling just by constantly playing year after year. Sometimes it's just good to remember why you're playing and stuff."

Top seed Osaka's win came on Rod Laver Arena, the main show court at the Melbourne Park complex that will stage the Australian Open later this month, when Osaka will be defending her title. Fellow seeds Liudmila Samsonova, Bernarda Pera and Alison Riske were beaten.

At the concurrent Melbourne Summer Set 2 event, American top seed Jessica Pegula was ousted in the first round by Romanian Irina-Camelia Begu, losing 7-6 (8-6) 6-3.

The Adelaide International 1 event contains the strongest field this week, and Tuesday saw straight-sets wins for Coco Gauff and a pair of 2020 grand slam winners in Iga Swiatek and Sofia Kenin.

Eighth seed Elina Svitolina had a bad day though, the Ukrainian losing 5-7 6-4 6-3 to Russia's world number 130 Anastasia Gasanova.

World number one Ash Barty will start her 2022 season at the Adelaide International along with eight of the other current 10 top players in the world.

Barty has held top spot in the women's rankings since September 2019 and collected five titles – including Wimbledon – in the 2021 season but missed the French Open with a hip injury.

She also opted to not play in the season-ending WTA Finals in Mexico due to coronavirus-enforced quarantine concerns that could disrupt her preparation for the following campaign.

The Women's Tennis Association (WTA) confirmed on Friday that Barty would begin her 2022 season in Adelaide on January 2, along with defending champion Iga Swiatek, WTA Finals victor Garbine Muguruza and Roland Garros winner Barbora Krejcikova, as the world's elite players prepare for the Australian Open.

The entry list for the WTA 500 tournaments also includes Tokyo Olympics gold medallist Barbara Bencic, who finished runner-up to Swiatek in 2021, former world number one Karolina Pliskova and US Open runner-up Leylah Fernandez.

The field boasts 12 major trophies between them, but three grand slam winners will kick-start their seasons in Melbourne the day after.

Naomi Osaka, who is aiming to defend her title at the Australian Open, gets her preparations underway in the Melbourne Summer Set.

Two-time major winner Simona Halep and reigning US Open champion Emma Raducanu will play in the Melbourne Summer Set.

The trio are among 20 of the top 50 ranked players in the world for the two WTA 250 tournaments starting on January 3, with the entry list split between the competitions the week before matches start.

Raducanu will feature in just her eighth Tour-level event, and her fourth tournament since winning her first major, while Osaka will be appearing for the first time since an early defeat in the third round of the US Open to Fernandez.

Novak Djokovic has been included in the official entry list for the 2022 Australian Open, with Tennis Australia adamant that no loopholes are being explored.

The world number one, who has won nine of his 20 grand slam titles in Melbourne, has not yet disclosed his COVID-19 vaccination status, meaning there is doubt over whether he will be able to participate.

Every person competing or attending the grand slam next month will need to have been fully vaccinated against coronavirus.

However, despite the uncertainty, the 34-year-old was named in the official list of players for the tournament draw.

Djokovic had already been named in Serbia's team for the ATP Cup, which is to be held in Sydney, leading to speculation that he could enter Australia by travelling directly to New South Wales, which has different COVID-19 restrictions to the state of Victoria, and may then seek a medical exemption to get around the rules applying to unvaccinated travellers.

James Merlino, Victoria's deputy premier, responded to these reports, which also suggested Djokovic had the backing of Tennis Australia.

"My view on this is really clear and really simple," Merlino said on Wednesday. "Everyone's looking forward to the Australian Open and everyone who will attend – spectators, players, officials, staff – everyone is expected to be fully vaccinated.

"They're the rules. Medical exemptions are just that – it's not a loophole for privileged tennis players. It is a medical exemption in exceptional circumstances if you have an acute medical condition."

Tennis Australia responded to Merlino's comments with a statement of their own.

"Any suggestion that Tennis Australia is seeking 'loopholes' within this process is simply untrue. Adjudicating on medical exemptions is the domain of independent medical experts. We are not in a position to influence this process and nor would we," the statement read.

"Any application for a medical exemption must follow strict government guidelines based on ATAGI (Australian Technical Advisory Group on Immunisation) clinical advice. This is the same process that applies to any person wanting to enter Australia."

While Djokovic's participation is unclear, Serena Williams is a big-name absentee. The 40-year-old, who is one shy of matching Margaret Court's record tally of 23 grand slams, had been expected to play in Melbourne.

Roger Federer had already confirmed his absence, but Rafael Nadal is set to compete for the first time since August.

World number two and US Open champion Daniil Medvedev takes his place in the draw, as does 2020 Australian Open finalist Dominic Thiem.

Australian world number one Ash Barty headlines the women's field, with Naomi Osaka, US Open winner Emma Raducanu and WTA Finals champion Garbine Muguruza also in the draw.

Bianca Andreescu, the 2019 US Open champion, has decided to skip the event to focus on her mental wellbeing.

Naomi Osaka has expressed her concern over the situation of Peng Shuai, who has not been heard from publicly since accusing China's ex-vice premier of sexual assault.

Peng, a Wimbledon doubles champion in 2013, posted allegations against Zhang Gaoli on Chinese social media site Weibo last week.

The post, along with all of Peng's other content, has since been removed from the site.

Multiple reports suggested the 35-year-old had subsequently not been seen or heard from, and the Women's Tennis Association (WTA) called for a full investigation into the matter.

There has so far been no response from the Chinese government to the allegations.

However, a spokesperson for the ministry of foreign affairs informed reporters he was not aware of the situation.

"I have not heard of the issue you raised," the spokesperson said via a widely released statement. "This is not a diplomatic question."

Now Osaka, a four-time major champion and one of the biggest names in the sport, has used her platform to question the situation.

"Hey everyone, not sure if you’ve been following the news but I was recently informed of a fellow tennis player that has gone missing shortly after revealing that she has been sexually abused," Osaka wrote in a statement published to her official Twitter account.

"Censorship is never ok at any cost, I hope Peng Shuai and her family are safe and ok. I'm in shock of the current situation and I'm sending love and light her way."

Osaka concluded her post with the hashtag: "#whereispengshuai".

On Sunday, WTA chairman Steve Simon addressed the matter in a statement that said: "The recent events in China concerning a WTA player, Peng Shuai, are of deep concern.

"As an organisation dedicated to women, we remain committed to the principles we were founded on – equality, opportunity and respect.

"Peng Shuai, and all women, deserve to be heard, not censored. Her accusation about the conduct of a former Chinese leader involving a sexual assault must be treated with the utmost seriousness.

"In all societies, the behaviour she alleges that took place needs to be investigated, not condoned or ignored. We commend Peng Shuai for her remarkable courage and strength in coming forward.

"Women around the world are finding their voices so injustices can be corrected.

"We expect this issue to be handled properly, meaning the allegations must be investigated fully, fairly, transparently and without censorship.

"Our absolute and unwavering priority is the health and safety of our players. We are speaking out so justice can be done."

Osaka's comments follow on from men's world number one Novak Djokovic expressing his concern over the situation when speaking to the media earlier this week.

Djokovic said: "I don't have much information about it. I did hear about it a week ago.

"Honestly, it's shocking that she's missing, more so that it's someone that I have seen on the tour in the previous years quite a few times.

"It's not much more to say than hope that she will be found, that she's OK. It's just terrible. I can imagine just how her family feels that she's missing."

Naomi Osaka is going to play tennis again and expects to feed her itch to return to the tour "soon".

Osaka said in the wake of her shock US Open third-round defeat to teenager Leylah Fernandez that she would take a break from the sport.

"I honestly don't know when I'm going to play my next tennis match. I think I'm going to take a break from playing for a while," Osaka told her post-match media conference following that loss.

She subsequently pulled out of Indian Wells but the four-time grand slam champion, who withdrew from the French Open back in May to protect her mental health, does not anticipate her absence being an extended one.

"I know I'm gonna play again, probably soon because I kind of have that itch again," Osaka told HBO's 'The Shop'.

"But it wouldn't really matter to me if I won or lost. I'd just have the joy of being back on the court.

"Just to, like, you know, that I'm doing it for myself."

Explaining her unhappiness on the court, Osaka added: "I started to feel like that power was being taken away from me.

"And the way that I felt, like, I wasn't playing to make myself happy and I was more concerned about … what would people say about me.

"I used to love the competition and just being competitive. Like if I were to play a long match, the longer it was the more fun it was for me.

"And then I just started to feel – recently – the longer it was the more stressed out I became. But I just needed a break to go within myself."

Former world number one Naomi Osaka unsurprisingly withdrew from next month's Indian Wells Masters, having flagged a break from tennis following her US Open meltdown.

The tournament confirmed 2018 champion Osaka's absence on Wednesday, with the Indian Wells Masters scheduled to take place from October 4-17 after the 2020 edition was cancelled due to the coronavirus pandemic.

Osaka's US Open title defence came crashing down in a remarkable 5-7 7-6 (7-2) 6-4 third-round capitulation at the hands of eventual finalist Leylah Fernandez earlier this month.

Up a set and serving for the match at 6-5 on Arthur Ashe Stadium, four-time major champion Osaka lost her cool and composure after throwing her racquet three times in an unsuccessful second-set tie-break.

Amid boos in New York, Japanese star Osaka was also warned after hitting a ball into the crowd at Flushing Meadows.

After the surprise exit, Osaka told reporters she planned to "take a break from playing for a while."

She added: "I feel like for me recently, like, when I win I don't feel happy. I feel more like a relief. And then when I lose, I feel very sad. I don't think that's normal. I didn't really want to cry.

"I feel like… this is very hard to articulate. I feel like I'm kind of at this point where I'm trying to figure out what I want to do, and I honestly don't know when I'm going to play my next tennis match [tearing up]. Sorry."

It comes following a difficult couple of months due to mental health concerns as a result of "long bouts of depression" since winning the 2018 US Open.

Osaka withdrew from May's French Open having won her first-round match, after she was fined and threatened with further punishment – and possible expulsion from the grand slam – for skipping obligatory media duties.

She subsequently pulled out of Wimbledon before returning for the Olympic Games, though she suffered a surprise loss on home soil in Tokyo and was reduced to tears during a news conference in Cincinnati.