Serena Williams' bid for a record-equalling 24th grand slam title started with a comprehensive win over Laura Siegemund at the Australian Open.

The American star was dominant on her way to a 6-1 6-1 victory over Siegemund on Rod Laver Arena on Monday.

Williams is aiming to join Margaret Court on a record 24 grand slam singles titles and she had no problems against the German in Melbourne.

She improved to 20-0 in the first round of the Australian Open, showing few signs of a shoulder injury she expects to be dealing with throughout the tournament.

Williams lost just 10 games in her previous two wins over Siegemund, but the seven-time Australian Open winner was broken in the opening game.

But Siegemund produced too many errors from then on, Williams winning in just 56 minutes to set up a clash against Nina Stojanovic.

Data Slam: Serena cruises after initial nerves
Williams was broken to 15 in the opening game when Siegemund produced a forehand return winner. However, she steadied, reeling off the next 10 games on her way to a comfortable win.

WINNERS/UNFORCED ERRORS
Williams – 16/15
Siegemund – 4/20

ACES/DOUBLE FAULTS
Williams – 4/1
Siegemund – 0/3

BREAK POINTS WON
Williams – 6/9
Siegemund – 1/1

Rafael Nadal is "doing everything possible" to play a part in the Australian Open after suffering from back pain for the past two weeks.

The 34-year-old pulled out of Spain's line-up for the ATP Cup earlier this week and was last in competitive action in November's ATP Finals.

Nadal is due to face Laslo Djere in the first round on Tuesday as he seeks a second Australian Open title, but the Spaniard cannot guarantee he will be able to play the match.

"It's not great, obviously," he said. "It's true that for the last 15 days I have been suffering.

"In the beginning, the muscle was just a little bit tired, but I now feel a little bit more stiff than usual.

"The muscle is still tight, so it is difficult to play with freedom of movement."

But Nadal, who has a history of back injuries, is refusing to withdraw from the tournament.

"I have Monday and then playing Tuesday. I don't think about not playing," he said.

"We are doing everything. My physio is here, the doctors [are] here, everybody is helping me in all possible ways. I hope to be ready, that's all. I know sometimes things change quick."

Nadal is not alone in entering the first grand slam of the year below full strength, with the likes of Serena Williams, Sofia Kenin and Naomi Osaka also battling injury problems.

However, the world number two will not use his niggling back issue as an excuse should he suffer an early exit at Melbourne Park.

"I'm not a big fan of finding excuses," he said. "When things happen, you need to find a way to get through."

Nadal can surpass Roger Federer for all-time majors should he triumph at the Australian Open.

He is also looking to become only the second man after Rod Laver to win each major on more than one occasion in the Open era, but his only previous success at the tournament came 12 years ago.

"I think I had the big chance in 2014. I got injured during the match on the back. It was tough," he said.

"I had another good chance in 2012, another good chance in 2017 with a break up in the fifth. I just didn't win the match. 

"That's all, I can't find another reason. It is true that I missed a couple of Australian Opens for injuries, too."

World number one Novak Djokovic said he does not have "much respect" for outspoken Australian star Nick Kyrgios away from the tennis court.

Kyrgios has been critical of Djokovic in an ongoing feud with the 17-time grand slam champion, who was labelled a "tool" by the former following a list of requests made to Tennis Australia (TA) and the Victorian government for tennis players stuck in hotel quarantine amid the coronavirus pandemic.

Former world number 13 Kyrgios was also critical of Djokovic's decision to stage the Adria Tour in Europe last August – in the midst of the COVID-19 crisis – having previously dubbed the Serb star "cringeworthy".

Djokovic rekindled his rivalry with Kyrgios after being asked about the 25-year-old on the eve of the Australian Open.

"I've said this before," Djokovic told reporters on Sunday. "I think he's good for the sport. Obviously he's someone that is different. He goes about his tennis, he goes about his off court things in his own authentic way. 

"I have respect for him. I have respect for everyone else really because everyone has a right and freedom to choose how they want to express themselves, what they want to do. My respect goes to him for the tennis he's playing. I think he's very talented guy. He's got a big game. He has proven that he has a quality to beat any player really in the world in the past.

"Off the court, I don't have much respect for him, to be honest. That's where I'll close it. I really don't have any further comments for him, his own comments for me or anything else he's trying to do."

Djokovic has won the past two Australian Open finals as he eyes a record-extending ninth Melbourne Park crown.

The 33-year-old, who opens his title defence against Jeremy Chardy on Monday, has won the Australian Open every time he has reached the semi-finals.

Djokovic has reached at least the semi-finals in seven of his last nine grand slam tournaments, winning five of them.

No male has won more Australian Open men's singles titles than Djokovic, who said: "It's a love affair. Probably something similar maybe not like Rafa [Nadal] has with the French Open, but I've been feeling more comfortable on the court each year that I've been coming back. 

"The more you win, obviously the more confidence you have and the more pleasant you feel on the court. It just feels right. If you're in the right state of mind, regardless of the surface, you have a better chance to play at your best.

"When I stepped on the court this year for the first time in the practice session, I relived some of the memories from last year, also the other years that I won the tournament here.

"It just gives me great sensation, great feeling, confidence. It feels right. It feels like the place where I should be and where I have historically always been able to perform my best tennis. Hopefully can be another successful year."

Asked if he still feels nerves, Djokovic – who is looking to close the gap on Rafael Nadal and Roger Federer (both 20) for the most slam trophies – added: "Every match, every match. Every single match. I don't want to speak on behalf of the other athletes, but I just feel like it's almost impossible to eliminate that kind of pressure, anticipation, the nerves coming into any match really for an athlete. At least in my case.

"It's just that I managed over the years to train myself, I think with the experience and with also the dedication that I had off the court to the mental preparation, that helped me react better to those kind of emotions. Sometimes I don't manage to overcome the pressures and the stress and nerves. Sometimes I do. It really just depends. Even though I've been blessed to experience a lot of success, especially here in Australia, but also in my career. I still feel that those failures, if you want to call them that way, even though I don't believe in failures, I just believe in opportunities to improve, kind of the lessons to be learned, but in those matches you lose, big matches, that's where you learn the most.

"That's where you're facing the kind of wall mentally. You're upset. You have a lot of different things happening, and you feel like you let yourself down. That's where it's the biggest opportunity for you to really address that and become stronger, more capable. You can get to know yourself a little bit on deeper levels. It still happens to me.

"Every single tournament, regardless of my previous success, of course I do feel that I have more confidence, more experience, maybe more training in understanding how to deal with these specific situations when I'm coming on the big court, being expected to win 99 per cent of the matches that I play.

"But it's still there. It's still there. I don't think it's ever going to go away. Especially when the occasion is big, when you're playing for the biggest trophies."

Has the time come for a former world number one to end her wait for a first grand slam title since becoming a mother?

It is a question that has been asked time and again since Serena Williams returned in 2018 following the birth of her daughter, Alexis Olympia.

The legendary American must have long since become tired of being asked whether she can match Margaret Court's record of 24 major singles triumphs, with her last success coming when she was pregnant at the 2017 Australian Open.

While the 39-year-old - beaten in four grand slam finals after coming back to the tour - will be expected to mount a challenge over the next fortnight, it could be another mother who is celebrating at Melbourne Park.

It is eight years since Victoria Azarenka claimed her second grand slam title at the Australian Open, but the 31-year-old has shown there could be more to come.

Azarenka beat Williams for the first time in a major to reach the final of the US Open last year, but she then endured the agony of losing to Naomi Osaka.

That was her first championship match at a grand slam in seven years, having given birth to her son, Leo, late in 2016 before a prolonged child custody dispute badly disrupted her career.

A resurgent Azarenka took her tally of WTA Tour singles titles to 21 by winning the Western and Southern Open last August and was named the Comeback Player of the Year for 2020, as she headed back towards the peak of her powers.

The world number 13 claimed both of her grand slam titles at the Australian Open and will face Jessie Pegula in the first round next week.

Azarenka said she is enjoying her tennis more than ever and Michael Joyce, her former coach, believes she has a great chance of making a dream start to the year.

Joyce, who also coached Pegula, told Stats Perform News: "Vika has got as good a chance as anyone in Australia. She's back at the top, where she belongs.

"She won the Western and Southern and came so close at the [US] Open. She's also had some very tough draws as she's worked her way back, so she's done incredibly well to get back where she is.

"Opponents won't want to play her. If Vika gets through a couple of rounds, she can be very dangerous. Once she gets momentum, she can be hard to stop."

The great Martina Navratilova declared after Azarenka's run to the final at Flushing Meadows that she had witnessed "a new Vika" with extra punch in her shots" and "stronger than ever before".

Azarenka's positive outlook has also been evident off the court, as she recently launched a 'Think About It' podcast series, in which she engaged in in-depth conversations with the likes of motivational guru Trevor Moawad and professional rock climber Sasha DiGiulian.

The aim of the series was for Azarenka and her audience to learn from 'power players' in a variety of industries and show the strength that can be forged from vulnerability.

Azarenka's rivals may be feeling vulnerable in Melbourne as they think about how to go about beating the Belarus-born star.

Rafael Nadal has history in his sights, but Novak Djokovic stands in his way at an Australian Open he has almost made his own.

With Roger Federer absent from the year's first grand slam, all eyes in the men's draw will be on Nadal and Djokovic.

As the fight between the 'Big Three' continues as to who will finish their career with the most majors, Melbourne shapes as again playing a key part, particularly amid the ongoing uncertainty due to the coronavirus pandemic. After winning his 13th French Open last year, the equation is simple for Nadal. His success at Roland Garros drew him level with Federer on 20 majors, the most by a man all-time.

But with the GOAT debate sure to continue for decades to come, a second title in Melbourne would also lift the Spaniard into uncharted territory. Nadal has the chance to become the first man in the Open Era to win every grand slam at least twice. Federer and Djokovic are both missing a second crown at Roland Garros.

For all his dominance in Paris, that would add another feather to the cap for 34-year-old Nadal. Most of Federer's major success has come at Wimbledon (eight titles), while Djokovic's has been at the Australian Open (also eight titles) – both establishing men's records at those tournaments. Nadal has been runner-up four times in Melbourne since his only title in 2009, while he has reached at least the quarter-finals in the past four years.

But just as Nadal, who is dealing with a back injury ahead of the tournament, stands in the way at the French Open, he will need to get past Djokovic – or have some luck – in Australia.

The Serbian has a 75-8 win-loss record at the tournament, including winning the past two titles. He has won the crown every time he has reached the semi-finals. Djokovic's previous blip in Melbourne came in 2017 and 2018, surprisingly beaten by Denis Istomin (second round) and Chung Hyeon (fourth round) respectively.

A year younger than Nadal, Djokovic is a 17-time grand slam champion, and he has made no secret of his desire to hold the record for most majors won by a man. Djokovic and Nadal have claimed nine of the past 10 majors, although the other one came recently as Dominic Thiem clinched last year's US Open, where the Spaniard and Federer were absent.

With preparations impacted by COVID-19, perhaps Thiem, Daniil Medvedev, Stefanos Tsitsipas, Alexander Zverev or Andrey Rublev could threaten as the wait goes on for a changing of the guard in men's tennis.

But all eyes are unsurprisingly on Nadal and Djokovic as history again beckons.

Naomi Osaka said the scheduling of lead-up events was a factor in her decision to withdraw from the Gippsland Trophy on Saturday.

The three-time major champion opted to pull out of her scheduled semi-final against Elise Mertens due to a shoulder injury.

Osaka, 23, was due to play a fourth match in five days, but decided to withdraw ahead of the Australian Open starting on Monday.

"Anyone that's kind of followed me for a bit knows that I've kind of had a slight shoulder thing since like 2018 in Beijing," the Japanese star told a news conference.

"It kind of flared up again because I played a lot of matches back-to-back. But, for me, my main focus is hoping I can rest enough before the Open."

Osaka, who will face Anastasia Pavlyuchenkova in the Australian Open first round, said the time between the Gippsland Trophy and year's first major also impacted her decision.

"I would say it is a factor because for me, I don't normally play the tournament right before a slam," she said.

"But I felt like it was really necessary to get matches in. I think everyone felt that way.

"I'm kind of sad that I wasn't able to play today. But I think in the end it's the right decision."

Serena Williams admitted she would be dealing with her shoulder injury during the Australian Open, but the star is "very confident" she will be ready to go.

Williams withdrew from the Yarra Valley Classic on Friday due to a right shoulder injury.

Asked how she was feeling on Saturday, the 23-time grand slam singles champion was upbeat.

"I feel pretty good. I've gotten a lot of treatment already on my shoulder.  But I'm super confident it's going to be great," Williams told a news conference.

"I'm feeling very confident, I think is a better word, and getting ready for hopefully the next two weeks."

However, Williams said the injury would be an issue throughout the Australian Open, which begins on Monday.

"It's definitely something that I'm going to have to deal with for the fortnight. Kind of knowing that going into a tournament definitely helps," the 39-year-old said.

"Also knowing, okay, I'm going to have to probably pick up some different therapy exercises after each match, etcetera.

"It's going to be really important."

Williams' last grand slam title came in Melbourne in 2017 and all eyes will again be on the American in her bid to equal Margaret Court's record of 24 major crowns.

While that record is again on her mind, Williams – who will face Laura Siegemund in the first round – said she was now more relaxed about it.

"It's definitely on my shoulders and on my mind. I think it's good to be on my mind," she said.

"I think it's a different burden, I should say, on my shoulders because I'm used to it now. It's more relaxing I would like to say, yeah."

Sofia Kenin insisted her leg injury was improving as she prepares for her Australian Open title defence.

In a rematch of last year's Australian Open decider, Kenin was crushed 6-2 6-2 by Garbine Muguruza in the Yarra Valley Classic quarter-finals on Friday.

Kenin, 22, said she struggled with a leg injury which she hopes will not affect her at Melbourne Park, where the year's first grand slam begins on Monday.

"It was my left groin and my left glute, it was completely sore," the American told a news conference on Saturday.

"I think I was rolling a lot yesterday. Even before the match I rolled probably like an hour before they even finished. I was just rolling with the Theragun. It kind of got better, but it wasn't the best. She obviously played well."

Kenin, who will face Maddison Inglis in the Australian Open first round, added: "It's better, which I don't understand. From a match, now today it's better. Thank God. Obviously I'm not going to complain about that. I want it to be better for AO."

The defending champion's injury worry is just the latest ahead of the Australian Open, with Serena Williams, Naomi Osaka and Victoria Azarenka among those withdrawing from lead-up tournaments.

Kenin believes quarantine ahead of events had an impact, as well as long lay-offs.

"People who haven't played matches for two weeks, it's obviously not the same. Everyone is using this tournament to prepare for Australian Open," she said.

"Obviously you can see that being in a room for two weeks, not playing, practising, it's not the same as playing a match clearly. After two matches, my leg is completely sore. 

"Yeah, it's obviously different. But everyone's obviously going to be ready for Australian Open, for sure."

Australian Open champion Novak Djokovic could face Dominic Thiem in a mouth-watering semi-final after being handed a tough path to success at Melbourne Park, where Serena Williams will continue her quest for a 24th grand slam singles title.

The Australian Open draw took place on Friday, with world number one Djokovic set to play Frenchman Jeremy Chardy in the opening round of the year's first major tournament.

Amid coronavirus concerns in Melbourne, where Swiss great Roger Federer is absent, Djokovic has set his sights on a ninth crown and 18th major success, but the top seed's title defence is far from straightforward.

Djokovic could face Gael Monfils (fourth round) and sixth seed Alexander Zverev (quarter-final) en route to a possible semi-final against US Open champion and third seed Thiem.

The Serb overcame Thiem in a five-set thriller in last year's Australian Open final, before the latter broke through for his maiden major trophy at Flushing Meadows.

Djokovic could then meet second seed and 20-time major champion Rafael Nadal in a blockbuster final – he blitzed the Spanish superstar in the 2019 Australian Open decider but lost in three one-sided sets in their previous meeting in the French Open final.

Nadal will go head-to-head with another Serb in the first round – Laslo Djere – while Stefanos Tsitsipas could await in the quarters, with 2019 US Open final opponent Daniil Medvedev also on the same side of the draw.

Meanwhile, Williams' bid for a record-equalling 24th slam will begin against German Laura Siegemund.

The 39-year-old Williams has been stuck on 23 majors since winning the Australian Open in 2017 – losing finals at Wimbledon (2018 and 2019) and the US Open (2018 and 2019).

World number one and local hope Ashleigh Barty will meet Montenegro's Danka Kovinic in round one and defending champion Sofia Kenin faces Australian wildcard Maddison Inglis.

The last 16 could see Williams clash with Aryna Sabalenka, Barty meet Petra Martic, Kenin tackle Johanna Konta and three-time major champion Naomi Osaka do battle with last year's runner-up Garbine Muguruza.

One in eight women in the Australian Open draw have already won a grand slam title.

One in eight. It is staggering that of the 128 players who set out in the hope of singles glory at Melbourne Park, there are 16 major champions among them, and perhaps never has it been so difficult to predict who will carry off the title.

Compare it to the men's draw, where there are just five grand slam singles winners, and where you would struggle to make a compelling case for any more than three of those this year, with apologies to Stan Wawrinka and Marin Cilic.

As long-running dynasties near their end on the men's and women's tours, the WTA is a lengthy step ahead of the ATP with a cast of appealing characters already assuming leading roles.

The leader of the pack

Three-time grand slam champion Naomi Osaka is at the forefront of a school of rising stars, but she has impressive rivals for company.

The last four years have seen the 15 women's majors won by 12 different players, whereas in the men's game, Rafael Nadal (6), Novak Djokovic (5), Roger Federer (3) and Dominic Thiem (1) have creamed off all the top prizes in the same period.

Often criticised in the past for a perceived lack of depth, in the years when Serena Williams won seemingly at will, the women's tour has exploded with a rush of bright and young talent.

Osaka is a revelation and a leader, on and off the court. Twice a US Open champion now, and a winner in Australia two years ago, the 23-year-old Japanese star took a powerful stance for racial equality at Flushing Meadows back in September, at the height of Black Lives Matter protests. She wants to achieve even more off the court than on it, where she looks assured of one day leaving an impressive legacy.

If there is any area where Osaka's game falls down it is consistency. She has surprisingly not passed the fourth round in 14 of her 17 grand slam appearances, but on every occasion she has gone beyond that stage it has been en route to lifting a trophy.

In hot pursuit

Last year's three slam champions were, at the times of their triumphs, just 21 (Sofia Kenin - Australian Open), 19 (Iga Swiatek - French Open) and 22 (Osaka - US Open).

The women's game has not seen anything comparable in terms of youthful winners of its blue riband tournaments since 2004, when the 21-year-old Justine Henin won in Australia, Anastasia Myskina landed the Roland Garros title at 22, Maria Sharapova was a 17-year-old bolter to Wimbledon glory and 19-year-old Svetlana Kuznetsova scored a stunning Flushing Meadows victory.

Last year does not touch the 1997 season, when a 16-year-old Martina Hingis won the Australian Open, Wimbledon and US Open, denied a grand slam clean sweep by 19-year-old Iva Majoli's shock French Open final win over the Swiss.

But women's tennis is still seeing a remarkable shift to relative youth.

The 2019 season saw a then 19-year-old Bianca Andreescu scoop a stunning US Open win, while Ash Barty took the French Open.

Andreescu has been sidelined with a knee injury since the 2019 WTA Finals, but she is back for Australia, where Queenslander Barty, now 24, is the home hero.

Brace for the prospect of Andreescu and Barty joining Kenin, Swiatek and Osaka in a group of five who can take the women's game boldly into the post-Williams era.

But the Williams era isn't over

This is true, and again Serena will make another attempt to land that elusive 24th grand slam, the one that would move her level with Margaret Court on the all-time list.

She remains, at the age of 39, a magnificent competitor and a beguiling player, as does sister Venus, who turns 41 in June.

Serena has lost her last four grand slam finals, however, and the most recent run to a title match came almost 18 months ago in New York, where Andreescu had her number.

As the new gang of five threaten to pull away from the old establishment, perhaps Williams is now in the next group, along with the likes of Simona Halep, Victoria Azarenka and Petra Kvitova: still perfectly capable of winning another slam or even multiple slams, but it feels important to strike now.

Serena has not won any of her last 10 slams, making it the longest span in her professional career without winning a major.

Barty party, or Sofia the second?

Osaka begins the Australian Open as favourite with bookmakers, but world number one Barty will have home support and could make that count. How she performs will be keenly watched, given she chose not to travel once the COVID-19 pandemic hit last year, sitting out 11 months.

Should Barty get on a roll, hopes will be high she can become the first Australian woman to take the title since Chris O'Neil in 1978. Last year, Barty fell in the semi-finals to Kenin, and she will be eager to land a second slam title.

Kenin, whose intense concentration and steely resolve helped her pull off last year's shock Melbourne win, and follow up with a run to the French Open final, can be a match for anyone. She will be aiming to become the first woman to win back-to-back Australian Open titles since Azarenka in 2012 and 2013.

Success on this level has come perhaps ahead of schedule for the American, and the same can be said for Swiatek, whose demolition of the field at Roland Garros in October made a mockery of her being ranked number 53 in the world.

The teenage Polish player became her country's first grand slam singles champion, and with that status comes the expectation she will follow it up. How that turns out for her will be one of the most intriguing of sub-plots in the new season.

Changing priorities

Halep said in a recent WTA interview that winning an Olympic medal was her "main goal" for 2021, although Osaka will also have the Tokyo Games firmly circled in her diary.

For the likes of those other players among the 16 slam winners in the Melbourne draw, there will be differing targets this year, too.

Angelique Kerber, Sloane Stephens, Jelena Ostapenko and particularly Garbine Muguruza may yet come good again on the big stage at some point this season.

For Venus Williams, Kuznetsova and Samantha Stosur, it may be a case of one final hurrah.

As the likes of Coco Gauff emerge as potential future big-stage winners, and fledgling ambassadors, the women's game looks in safe hands.

Australian Open tournament director Craig Tiley said there were no plans to change the schedule for the major amid coronavirus concerns.

More than 500 players and officials were forced into isolation after a worker at an Australian Open quarantine hotel tested positive for COVID-19.

It led to play at lead-up events in Melbourne on Thursday being called off and sparked fears around the year's first grand slam, which is scheduled to begin on Monday.

But Tiley is hoping play is back underway on Friday and said he expects the Australian Open to start as scheduled.

"The intention is to start the Australian Open on Monday so there's no intention of changing the time for the Australian Open," he told a news conference.

Tiley added: "We're absolutely confident the Australian Open is going to go ahead.

"We know that we've got a period now that we've got to work through with those 507 players and their staff, 160 players actually, that need a test and we fully expect the probability is very low that there's going to be any issue.

"We fully expect them all to test negative and then we continue with play tomorrow like we originally planned and if we have to go through this again we'll continue to go through this again and we've got another three and a half weeks of tennis, we've got a lot of tennis to play and fully expect to keep the original schedule once we get past today."

The draw for the Australian Open was pushed back to Friday, while crowds are still expected to be in attendance for the major.

Preparations for the Australian Open were dealt a fresh blow on Wednesday when a member of hotel staff tested positive for coronavirus, although Victoria's premier insists the tournament is not under threat at this stage.

A 26-year-old worker at the Grand Hyatt Hotel returned a negative test at the end of his previous shift on January 29 but subsequently developed symptoms and tested positive on Wednesday.

As a result, Melbourne and the wider Victoria region has reverted to its New Year's Eve restrictions of gatherings at home being limited to 15 people and masks having to be worn in public indoor spaces.

In terms of the specific impact upon participants in the Australian Open, players, officials and support staff who were staying at the hotel during this period must now isolate and undertake a COVID-19 test.

The number of tournament-related personnel classed as "casual contacts" related to the incident is estimated to be between 500 and 600.

Nevertheless, Victorian premier Daniel Andrews told a news conference he was confident the Australian Open would go ahead as planned, even though the requirement that some players isolate and test could have an impact upon warm-up tournaments that are ongoing at Melbourne Park.

"There's about 500-600 people that are either players and officials and others who are casual contacts," Andrews said.

"They will be isolating until they get a negative test and that work will be done tomorrow so it might have an impact on tomorrow's play in the lead-up event, but at this stage there's no impact to the tournament proper.

"That's important to us, but the issue we're most focused on is much broader. That's about public health and public safety and that's why we've really pounced on this."

The Australian Open is scheduled to run from February 8-21.

Roger Federer is aiming to make his return to the ATP Tour at the Qatar Open, while Rafael Nadal is contending with a back injury with less than a week until the Australian Open.

Swiss maestro Federer has not played since losing in the semi-finals at Melbourne Park to Novak Djokovic in 2020 having undergone knee surgery last year.

The 20-time grand slam champion opted not to play in Australia this year but is aiming to return in Doha in March.

"I want to celebrate great victories again. And for that I am ready to go the long, hard road," Federer, a three-time champion at the tournament, said in an interview with SRF.

"I wanted to make my comeback at a smaller tournament so that I wasn't fully in focus and where the stress is also a little less."

Federer said it "hurts" to miss out in Australia but still has lofty ambitions at Wimbledon, the Olympics and the US Open in 2021, while saying he will attempt to play on clay this year.

"I'll try to play on clay again. The whole thing, of course, with regards to Halle, Wimbledon, the Olympics and the US Open," he added.

Federer's on-court rival Nadal matched the Swiss for most grand slam singles titles won by a male player after winning the French Open last year.

But his chances of going one better may be hindered by a back issue that forced the Spanish great to sit out his country's ATP Cup opener against Stefanos Tsitsipas on Tuesday.

"Hi all, we have decided with #TeamSpain and my team, to not play today the first match of the @ATPCup here in #Melbourne since I have a stiff low back. Hopefully I'll be better for Thursday," Nadal posted on Twitter.

Serena Williams and Simona Halep started the season with straight-sets victories in Melbourne a week before the Australian Open gets under way.

Williams and Halep played in an exhibition event with a crowd of 4,000 watching on in Adelaide last Friday and they were back in competitive action three days later.

Legendary American Williams beat Daria Gavrilova 6-1 6-4 to move into the third round of the Yarra Valley Classic.

The fifth seed struck 27 winners to 15 unforced errors on Margaret Court Arena as she set up a meeting with Tsvetana Pironkova, who ousted Donna Vekic 1-6 6-4 6-2.

Williams said: "It was a good match for me. It wasn't easy at all. It was lots of rallies and lots of movement, and she's from here, so she obviously always plays hard. So it was really good and it felt good to clinch that in the end."

Third seed Karolina Pliskova, Petra Martic, Danielle Collins and Marketa Vondrousova also advanced to the last 16 on Monday.

Elsewhere, top seed Halep is through to the third round of the Gippsland Trophy following a 6-4 6-4 win over Anastasia Potapova.

Halep hit 23 winners and broke twice in each set in what was her first official match since October.

Elina Svitolina, the third seed, beat Andrea Petkovic 6-1 6-4, while Coco Gauff, Ekaterina Alexandrova and Jelena Ostapenko were among the other winners seven days prior to the start of the first grand slam of 2021.

The Australian Open is set to welcome up to 30,000 spectators each day when the tournament begins on February 8 in Melbourne.

Local officials have given the go-ahead for fans to head to Melbourne Park, predicting a near-normal atmosphere when action begins at the year's first grand slam.

Last year's US Open was contested behind closed doors in New York, while only 1,000 paying fans were allowed at Roland Garros on each day of the 2020 French Open.

However, the COVID-19 crisis has been tightly managed in Australia, to the point where it was reported on Saturday that there had been no new local cases in the state of Victoria for 24 days.

The crowds will be split between day and evening sessions, and the number of fans allowed will drop to 25,000 for the final six days of the tournament, when fewer courts will be in operation.

Saturday's announcement means the event will be capped at around 50 per cent of capacity.

Tournament director and Tennis Australia chief executive officer Craig Tiley said it had taken "a massive team effort" to accommodate the arrival of around 1,000 players and officials into the country, with all required to spend two weeks in quarantine.

Victoria sports minister Martin Pakula said on Sky News Australia: "On Rod Laver Arena, as we get towards the end of the tournament, we'll have an incredible atmosphere – not that different to the atmosphere we've seen in all the Opens in the years past.

"That's really a testament to the work Victorians have done to get our numbers to zero but also the extraordinary work that Craig and the team at Tennis Australia has done."