A further 25 players have been forced into hard lockdown for two weeks prior to the Australian Open, tournament organisers have confirmed.

Tennis' season-opening grand slam was plunged into crisis on Saturday when it was announced 47 players would be consigned to their hotel rooms for 14 days and not eligible to practise.

Officials said the protocols were as a result of two passengers testing positive for coronavirus on a flight from Los Angeles that arrived on Friday morning, along with another passenger who flew in from Abu Dhabi.

That affected 24 players aboard the LA flight and 23 on the plane from Abu Dhabi, while another positive test for a passenger arriving in Melbourne from Doha on Saturday morning has taken the total number of players affected to 72.

A statement from the Australian Open read: "One positive COVID-19 test has been returned from a passenger on a charter flight into Melbourne from Doha which arrived at 5.30am on January 16.

"The passenger is not a member of the playing contingent and had tested negative before the flight.

"There were 58 passengers on the flight, including 25 players. All are already in quarantine hotels.

"The 25 players on the flight will not be able to leave their hotel room for 14 days and until they are medically cleared. They will not be eligible to practise."

About 1,200 players and staff have been arriving in Melbourne on sparsely populated aeroplanes ahead of the delayed Australian Open, which is due to get under way on February 8.

Speaking on Saturday, Tennis Australia CEO Craig Tiley insisted the tournament would be going ahead despite the chaos and the lack of preparation time for many of the playing contingent.

"It's not something we wanted to happen," he told The Today Show. "We were hoping every flight would be okay. We're in this situation, we have to deal with it.

"The Australian Open is going ahead and we'll continue to do the best we can possibly do to ensure those players, who are not in a great position, find it somewhat acceptable.

"We're planning on February 8, we do have that buffer time in there. We're looking forward to welcoming fans to the Australian Open.

"Ticket sales have been going well, we've got two weeks of great tennis and our intention is to continue with those dates."

Madison Keys is set to miss the Australian Open after testing positive for coronavirus.

The 2017 US Open runner-up announced on Thursday that she contracted COVID-19 before she was due to fly out for the first grand slam of the year.

Keys did not state she will definitely miss the major, which starts on February 8, but it appears the American will not make the trip to Melbourne.

The American wrote on Instagram: "Hi everyone, I wanted to let you know that I unfortunately tested positive for COVID-19 before I was supposed to fly to Australia.

"I'm very disappointed to not be able to play in the coming weeks after training hard in the off-season and knowing Tennis Australia and the tours did so much to make these events happen.

"I am self-isolating at home and will continue to follow all the necessary health precautions. I look forward to being back on tour next month."

It was revealed earlier in the day that three-time major winner Andy Murray has also tested positive for the virus, but still hopes to play in the Australian Open.

Meanwhile, world number 50 Tennys Sandgren was cleared to board a flight from the United States bound for Melbourne despite revealing he returned a new positive coronavirus test this week. 

The American, twice a quarter-finalist at Melbourne Park, initially posted to social media on Wednesday that he had tested positive for the virus for a second time. 

Although his first instance of having the illness was recorded in November, the 29-year-old's participation in the tournament appeared to be in doubt. 

But as he continued to update followers through the day, it emerged he had been allowed to board his flight. 

Players will only be allowed into Australia with proof of a negative test just prior to departure, or with approval to travel as a recovered case at the complete discretion of an Australian government authority.

Anyone wanting to travel out for the tournament who previously tested positive is required to provide additional and highly detailed medical information as proof they are a recovered case and no longer infectious or a risk to the community.

Aryna Sabalenka is keen to continue her hot streak after claiming a third consecutive title on the WTA Tour with a commanding victory over Veronika Kudermetova at the Abu Dhabi Women's Tennis Open.

Following season-ending triumphs in Ostrava and Linz, the world number 10 extended her ongoing winning run to 15 matches, prevailing 6-2 6-2 in an hour and five minutes.

"I'm really happy to keep winning and I’ll do everything I can to keep winning," Sabalenka told reporters. "Nobody likes to lose!"

"Every final is really something special and I would say finals are a different competition.

"This final was really nice and I would say a really fast game."

The pace of the contest owed much to Sabalenka's power game, with the Belarusian hitting 18 winners to her opponent's 13, while Kudermetova leaked 24 unforced errors to 13.

Sabalenka's clinical confidence was in evidence as she dispatched six of 12 break points fashioned.

"I’m really proud that I was fighting no matter what," she said of a run that has now yielded titles seven, eight and nine of her career.

"Some matches, I didn't feel my serve, some matches I didn't feel my forehand or backhand, but I would just keep fighting, finding my shots, and that this is what I’m really proud of, and really happy with this title."

Aryna Sabalenka will face Veronika Kudermetova in the Abu Dhabi Women's Tennis Open after extending her magnificent career-best winning run with a straight-sets victory over Maria Sakkari.

Sabalenka ended 2020 in red hot form and has carried on where she left off at Zayed Sports City International Tennis Centre to stand on the brink of claiming a third successive title.

The fourth seed from Belarus has now won 14 consecutive matches following a commanding 6-3 6-2 success over Sakkari on Tuesday.

Sabalenka reached the 13th WTA singles final of her career at the age of only 22, taking just 57 minutes to see the back of ninth seed Sakkari.

The world number 10 struck 22 winners, eight of which were aces, and made only eight unforced errors, while winning 83 per cent of points on her first serve and will be one to watch at the Australian Open next month.

Kudermetova will be playing in her maiden WTA singles final following a 7-6 (10-8) 6-4 victory over Marta Kostyuk of Ukraine.

Russian Kudermetova came from a break down in the first set and was behind in the tie-break, but dug deep to edge in front in a battle between two unseeded semi-finalists.

The world number 46 broke Kostyuk three times in the second set to secure her spot in the championship match, in which she will have to improve on a first-serve percentage of just 46.5.

The top two seeds are both out at the Abu Dhabi Women's Tennis Open after Sofia Kenin and Elina Svitolina suffered quarter-final defeats on Monday.  

Kenin had won the two previous meetings against Maria Sakkari and appeared on course to retain her 100 per cent record when cruising through the opening set.  

However, Sakkari hit back to stun the top seed, dropping just two more games as she rallied in emphatic fashion to triumph 2-6 6-2 6-0 after one hour and 23 minutes on court.  

"I think I did way too many errors and I was hitting too big when I didn't have to. But I'm glad that once again I found the way to turn the match around," the ninth seed told reporters.

Next up for Sakkari will be Aryna Sabalenka, who extended her impressive winning run to 13 matches after coming through a three-set tussle with Elena Rybakina.  

The fourth seed has not lost since going out at the 2020 French Open to Ons Jabeur - a result she avenged when the pair met on Sunday in the last eight in Abu Dhabi.  

In the other half of the draw, Veronika Kudermetova once again got the better of Svitolina, ending the second seed’s hopes of success in the tournament. 

Russian Kudermetova – who won their only previous meeting on the WTA Tour – came out on top in the deciding tie-break to triumph 5-7 6-3 7-6 (7-3).  

She will take on another player from Ukraine next, Marta Kostyuk overcoming a nightmare opening set to beat Spaniard Sara Sorribes Tormo 0-6 6-1 6-4 and reach the last four.

Sofia Kenin and Elina Svitolina fought back from the brink of defeat as both reached the Abu Dhabi Women's Tennis Open quarter-finals on Sunday.

Top seed Kenin fended off a match point in the second set before battling to a 3-6 7-6 (7-5) 6-4 victory over Yulia Putintseva at Zayed Sports City International Tennis Centre.

Putintseva was serving for a straight-sets win at 6-5 up in the second, but the tenacious Kenin forced a tie-break and rallied from 3-1 down to take the third-round match the distance.

The Australian Open champion secured three breaks in the decider to reach the last eight, hitting 35 winners to 25 from 13th seed Putintseva to set up a showdown with Maria Sakkari.

Svitolina, the second seed, was also on the verge of crashing out, but she hung in there to pull off a 6-2 6-7 (5-7) 7-6 (10-8) win over Ekaterina Alexandrova.

The world number five was a break down in the final set and saved two match points in a tense tie-break before finally seeing the back of her Russian opponent.

Ninth seed Sakkari beat two-time grand slam champion Garbine Muguruza 7-5 6-4 to give herself the opportunity to get the better of Kenin for the first time in three attempts.

Aryna Sabalenka stretched her impressive winning streak to 12 matches with a 6-2 6-4 success over Ons Jabeur, while Marta Kostyuk, Sara Sorribes Tormo, Elena Rybakina and Veronika Kudermetova also progressed.

Karolina Pliskova has crashed out of the Abu Dhabi Women's Tennis Open in the second round, while Coco Gauff was also eliminated.

Third seed Pliskova suffered a stunning 6-2 6-4 defeat to Anastasia Gasanova, a qualifier ranked at 292 in the world.

Pliskova fell to defeat in only 75 minutes on Saturday, the first time she had lost to an opponent outside of the top 50 in over a year.

Gasanova, 21, beat Mona Barthel in her WTA main draw debut this week and went on to save five of the six break points she faced to record an even bigger upset against Pliskova.

"It was not me on the court," a stunned Gasanova said after winning in her first match against a top-100 player, booking a last-16 clash against Sara Sorribes Tormo.

"I was so sure of myself. I'm really happy right now.

"I'm really surprised, but when I woke up today, I thought, 'Why not? Why can't I win this match?'

"Actually, I thought I would lose in qualies or something like that, but I just kept pushing myself, like, I need to win and I want to win.

"I had a [2021] goal to be top 200, actually! I don't know if I did this today, but that's my goal. 

"To play against a top-10 player is a great opportunity for me, and it's a great chance to show how I could play."

Pliskova, therefore, starts her year on a negative note, but there were no such problems for second seed Elina Svitolina, who was a 6-4 6-1 winner against Vera Zvonareva.

Last year's Australian Open finalist Garbine Muguruza cruised through with a 6-1 6-4 victory over Aliaksandra Sasnovich and sixth seed Elena Rybakina won in straight sets against Xiyu Wang.

Muguruza will face Maria Sakkari in an intriguing last-16 match next after the Greek ended the hopes of American Gauff with a comfortable 7-5 6-2 victory.

Top seed Sofia Kenin, who made two grand slam finals last year and won in Melbourne, will resume her campaign against Yulia Putintseva on Sunday.

Sofia Kenin admitted she was given a stern test by Kirsten Flipkens before the Belgian was forced to abandon their tussle at the Abu Dhabi Women's Tennis Open.

With a month to go before Kenin begins the defence of her Australian Open title, the American world number four was fighting to avoid a second-round exit to an experienced opponent.

Flipkens took the first set 7-5 and trailed 5-4 in the second, a break down, when an injury to her left ankle caused her to retire from the match.

A run of three consecutive games and 12 unanswered points from Flipkens had seen the 34-year-old former Wimbledon semi-finalist snatch the opener.

Kenin was turning the contest around in the second set and the top seed admitted she was "a little bit upset" to see Flipkens suffer when injury struck.

"We're good friends and that's not something you like to see," Kenin said, quoted on the WTA website. "I just hope [Flipkens] can have a speedy recovery and get ready for Australia.

"She played a really good match. It was the third time we’ve played each other, and it was a really solid match from both of us. This is not the way I wanted to win."

Aryna Sabalenka could be a player to fear at Melbourne Park in February, as the world number 10 made it 11 consecutive match wins by fending off Australian Ajla Tomljanovic 7-5 6-4.

Sabalenka finished off the 2020 season with titles in Ostrava and Linz so the Belarusian is looking for a hat-trick of tournament triumphs.

Tunisian Ons Jabeur scored a 5-7 6-3 6-2 victory against Kateryna Bondarenko of Ukraine to reach the last-16 stage, and she faces Sabalenka next.

Jabeur won on the only previous occasion she and Sabalenka have met, securing a three-set win in round three of the delayed 2020 French Open.

Dayana Yastremska says she is "astonished" after the world number 29 was provisionally suspended for failing an out-of-competition doping test.

The International Tennis Federation (ITF) on Thursday revealed Yastremska was charged on December 22, having tested positive for mesterolone metabolite in a sample taken on November 24.

Ukrainian Yastremska, who reached a career-high 21st in the rankings 12 months ago, says she is not guilty of any wrongdoing and will do all in her powers to clear her name.

The 20-year-old posted on Twitter: "I firmly state that I have never used any performance-enhancing drugs or any prohibited substances.

"I am astonished and under shock, particularly given that two weeks prior to this test - on 9 November 2020 - I tested negative at the WTA event in Linz. After this last tournament of the year, I stopped practising to rest prior to the start of the new season.

"Only a very low concentration of mesterolone metabolite was detected in my urine. Given that low concentration and given my negative test two weeks earlier, I have received scientific advice that the result is consistent with some form of contamination event.

"Besides, I have been informed that this substance is meant for use as medication by men and that women are advised not to use it due to the adverse effects it causes."

Yastremska said she was "resolutely determined to do everything to clear my name".

Rising star Yastremska has three WTA singles titles to her name.

Sofia Kenin and Coco Gauff both made it through to the second round of the Abu Dhabi Women's Tennis Open on a day of few shocks. 

Seven of the nine seeds in action on Thursday advanced, with only Marketa Vondrousova and Jennifer Brady falling by the wayside. 

Those upsets came despite Vondrousova and Brady each winning their opening sets - against Hsieh Su-wei and Tamara Zidansek respectively - the latter racing through 6-0 in the first before being reeled back in. 

Kenin and Gauff had no such problems, however. 

But top seed Kenin - the 2020 WTA Player of the Year - had to stay patient as she took down 789th-ranked Yang Zhaoxuan 7-6 (7-4) 6-2. 

The first set lasted more than an hour and saw Kenin face five break points, defending each of them, with another 11 Yang opportunities following in the second, although the world number four proved more clinical en route to victory. 

"It was the first match, obviously a bit of nerves, I had to find my groove," Kenin said afterwards. "Conditions weren't easy, it was quite windy.

"The first set was tough for me. I couldn't find the ball, I guess." 

Gauff was comfortable throughout, meanwhile, swatting aside Ulrikke Eikeri 6-0 6-1 to tee up a meeting with Maria Sakkari. 

Elina Svitolina, Karolina Pliskova and Aryna Sabalenka each also progressed in two sets, as did Garbine Muguruza, overcoming a potentially tricky hurdle in the form of Kristina Mladenovic. 

Muguruza was a 6-2 6-4 winner and afterwards said: "I was trying to do my game, dominating, not letting her dominate the point. 

"It's the first match of the year, it's a little bit tricky to get the feeling, but I'm happy with the win." 

Veronika Kudermetova started the new season in style by beating 10th seed Anett Kontaveit in the first round of the Abu Dhabi Women's Tennis Open on Wednesday.

Kudermetova had won her only two previous singles matches against Kontaveit and maintained that perfect record with a 7-5 6-1 victory.

The world number 46 from Russia broke four times to seal her place in the second round, with Kontaveit winning just 48.4 per cent of points on her first serve in a rusty beginning to the 2021 campaign.

Donna Vekic was another seed to fall at the first hurdle as Bernarda Pera consigned the Croatian to a 7-6 (12-10) 2-6 6-4 defeat at Zayed Sports City International Tennis Centre.

Kirsten Flipkens could face top seed Sofia Kenin in the second round after defeating Laura Siegemund 5-7 7-5 6-4.

Ons Jabeur is aiming to break into the top 10 this year and the 15th seed got up and running for the season by seeing off Anastasia Pavlyuchenkova 7-6 (7-3) 6-3.

Daria Kasatkina, Yulia Putintseva and Ajla Tomljanovic were among the other players who advanced to round two.