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.

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.

Rafael Nadal wants to play at the Olympics but the star said fitting more quarantining into the ATP Tour calendar looked "difficult".

After being postponed last year due to the coronavirus pandemic, the Games are scheduled to start in Tokyo on July 23.

Naomi Osaka said she would be willing to quarantine ahead of the Olympics, with players having gone through similar in preparation for the Australian Open.

Nadal, an Olympic gold medallist in singles and doubles in 2008 and 2016 respectively, said he would listen to the experts, but acknowledged quarantining could be tough.

"It's the same as always. I am nobody to have a clear opinion on that.  I am just a tennis player, a human person that doesn't have enough knowledge about all the situation," the Spanish star told a news conference on Sunday.

"What we have to do is just follow the instructions of what the people who really have the right knowledge of all this stuff give to us. What's going to happen in Tokyo for the Olympics, if the Olympics are going to happen or not, or if we have to do quarantine before Olympics for 15 days or not, seems like a sports perspective very difficult because it's difficult for us, I don't know, combining our Tour with another 15 days of quarantine to play Olympics. It looks difficult to fix it in our calendar.

"But, as I said, we're going to do what the people who know about virus and who know about protecting the people in every single country, [we] are going to just follow their instructions."

Asked if his intention was to go, Nadal said: "I think everybody wants to play in Olympic Games, then let's see what's going on."

Nadal and Spain will begin their ATP Cup campaign against Australia on Tuesday.

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."

Serena Williams and Rafael Nadal agreed it was great to be playing in front of busy grandstands again as tennis stars emerged from lockdown in Australia.

The women's and men's tennis tours have been contested largely behind closed doors over the past year, and a number of tournaments, most notably Wimbledon, have been cancelled due to the COVID-19 crisis.

The Australia public has given a cautious welcome to the arrival of the world's leading players, who have been quarantining in hotel rooms for much of the past fortnight, only allowed to briefly leave in order to train.

Ahead of the Australian Open, which begins on February 8 in Melbourne, Williams and Nadal are among a star-studded set of players who travelled to Adelaide to feature in the 'A Day at the Drive' exhibition event.

They both scored victories on Friday, with Williams defeating US Open champion Naomi Osaka 6-2 2-6 10-7 and Nadal snatching a 7-5 6-4 win over Dominic Thiem.

The delight in both at seeing crowds at a tournament was plain, with Williams saying in an on-court interview: "Thanks everyone for having us. We haven't played in front of a crowd in over a year. It's been a really long time."

In fact, it has not quite been a full year since the tours locked down initially, as it was early March when most tournaments began to be called off, with crowds frozen out.

Williams said the reception made the difficult past fortnight, being hidden away from the world, worth the strain for the players.

"This is really cool and then for having us and trusting us with your laws was great," said the 23-time grand slam winner. "We were so excited to be here and it's worth it."

Nadal said he was "super happy" to still be playing at the highest level and back in front of Australian crowds.

The pandemic has been carefully managed to the point where very few have the virus and it is considered safe to allow crowds into sporting events in the country.

Nadal said: "Hopefully this situation will go away quick and we will be able to enjoy fans on court [around the world].

"We're super excited to have fans at the Australian Open and today."

That optimism and excitement was shared by men's world number one Novak Djokovic, who played just one set against Jannik Sinner due to a problem with blisters on his right hand.

Eight-time Australian Open champion Djokovic told fans: "Thank you so much for coming out and making our day and making our year.

"We didn't play in front of this much crowd for 12 months. This is definitely something very special.

"It wasn't easy, obviously, with 14 days being constrained in the room and a few hours to train, but at the end of the day it was worth it because you guys made it very special today for us."

Novak Djokovic apologised but confirmed he had been dealing with a blister after only playing a set of his exhibition match in Adelaide.

The world number one had reportedly withdrawn and was replaced by Filip Krajinovic for a clash against Jannik Sinner.

But Djokovic played the second set, winning it 6-3 after Krajinovic had taken the opener 6-3 on Friday.

The 17-time grand slam champion, who had a blister on his right hand, apologised after the match.

"I'm sorry that I didn't step in on the court from the beginning," Djokovic told Channel 9.

"I had to do some treatment with my physio and wasn't feeling my best the last couple of days, I didn't know how I'm going to react.

"I wanted to play and I wanted to get out here and hopefully it was enough for you guys to see all three of us performing in front of you on the court today, I hope you enjoyed."

Djokovic, who came out of hotel quarantine on Friday, said he could not pass up the opportunity to play in front of fans.

"It's not easy but it's part of what we do. We are professional athletes we learn over the years to play with the pain and it's just a question and case whether that pain is bearable or not," he said.

"Obviously coming off from the hard training block and having an ATP Cup and Australian Open around the corner you don't want to risk it too much.

"But the emotion was so strong in me to come out on the court today seeing almost full stands, I had to play, that's it, I had to play."

Djokovic is due to play the ATP Cup starting on Tuesday, before the Australian Open begins on February 8.

Andy Murray has withdrawn from the Australian Open a little over a week after testing positive for coronavirus.

Murray, a five-time finalist in Melbourne, went into isolation at home after returning a positive test on January 14.

The three-time major winner, ranked 123rd in the world, had hoped to compete at the first grand slam of the year after being granted a wildcard.

However, tournament organisers indicated it would be difficult for Murray to remain in the draw as he would be unable to travel via one of the official charter flights containing other players before going through the required period of quarantine.

On Friday, the 33-year-old confirmed he had been unable to come to a "workable" solution with authorities.

In a statement carried by The Guardian and other UK media outlets, Murray said: "Gutted to share that I won't be flying out to Australia to compete at the Australian Open.

"We've been in constant dialogue with Tennis Australia to try and find a solution but we couldn't make it work.

"I want to thank everyone there for their efforts, I'm devastated not to be playing out in Australia. It's a country and tournament that I love."

The build-up to this year's Australian Open has been impacted by players having to spend a two-week quarantine in their hotel accommodation.

A total of 72 competitors have been unable to leave their rooms after positive coronavirus tests among passengers on the chartered flights to Melbourne.

Players have been unable to access practice courts and many have complained on social media about sub-standard food and conditions, with Yulia Putintseva, the world number 28, sharing videos showing mice in her room.

The tournament is due to start on February 8.

Novak Djokovic has denied he was being "selfish, difficult and ungrateful" in making suggestions for easing quarantine restrictions ahead of the Australian Open.

Djokovic came in for criticism after it emerged he had sent Australian Open tournament director Craig Tiley a list of potential ways for lockdown conditions to be improved for players who are under a strict lockdown in Melbourne.

Less than three weeks before the first major of the year gets under way, 72 players are consigned to their hotel rooms due to positive coronavirus tests on their flights to Melbourne.

World number one Djokovic does not have to adhere to such stringent rules in Adelaide, as he arrived on a virus-free flight.

The 17-time grand slam champion was labelled a "tool" by Nick Kyrgios after he was said to have asked for less time in isolation for players, requested they are given private housing with access to training courts, and better food.

Djokovic responded on Wednesday by stating that he was only trying to look out for his fellow players and expressed his gratitude to tournament organisers, the Australian government and the people of Melbourne.

He posted on social media: "My good intentions for my fellow competitors in Melbourne have been misconstrued as being selfish, difficult and ungrateful. This couldn't be farther from the truth

"I genuinely care about my fellow players and I also understand very well how the world is run and who gets bigger and better and why.

"I've earned my privileges the hard way and for that reason it is very difficult for me to be a mere onlooker knowing how much every help, gesture and good word mattered to me when I was small and insignificant in the world pecking order.

"Hence I use my position of privilege to be of service as much as I can where and when needed."

The Serb added of his correspondence with Tiley: "In our email exchange I used an opportunity to brainstorm about potential improvements that could be made to the quarantine of players in Melbourne that were in full lockdown.

"There were a few suggestions and ideas that I gathered from other players from our chat group and there was no harm intended to try and help.

"I was aware that the chances were low that any of our suggestions would be accepted, just like my request to quarantine with my team in Melbourne instead of Adelaide was denied prior to our travel because of the strict government regulations.

"I understand that organising international sporting events during a pandemic poses health risks to the local community and to the players themselves.

"Therefore, I would like to express my full gratitude to Tennis Australia, the Australian Government and local citizens for being willing to take this risk with us for the love of the game and the multiple opportunities it brings to the economy of the country and its people.

"We are honoured and we will all do our best to follow the guidelines and protocols put in place. We do hope that we will be able to nurture our bodies and be ready for the mental and physical endurance and strength tests that are ahead of us once the competition starts.

"Things in the media escalated and there was a general impression that the players [including myself] are ungrateful, weak and selfish because of their unpleasant feelings in quarantine. I am very sorry that it has come that because I do know how grateful many are.

"We all came to Australia to compete. Not being able to train and prepare before the tournament starts is really not easy. None of us ever questioned 14 days of quarantine despite what is being said by media outlets."

Victoria Azarenka called for greater understanding from players stuck in hotel quarantine ahead of the Australian Open.

After being exposed to coronavirus on flights, 72 players – including Azarenka – have been forced into a two-week quarantine ahead of the tournament beginning on February 8.

Novak Djokovic reportedly made several requests, which were rejected, of officials for players in quarantine, while Roberto Bautista Agut compared the conditions to prison.

But amid complaints on social media, two-time Australian Open champion Azarenka pleaded for players to be more understanding in a measured statement.

"Dear players, coaches, entourage and Australian community. I would like to take a moment and address some of my colleagues as well as the media around the world," the Belarusian wrote on Twitter.

"This has been a very difficult time for a lot of us that did not expect to end up in the situation we are in today, myself included. To be in a 14-day hard quarantine is very tough to accept in terms of all the work that everyone has been putting in during their off-season – to be prepared for playing our first grand slam of the year. I understand all the frustration and feeling of unfairness that has been coming and it is overwhelming.

"We have a global pandemic, nobody has a clear playbook of how to operate at full capacity and without a glitch, we all have seen it last year. Sometimes things happen and we need to accept, adapt and keep moving.

"I would like to ask all my colleagues for cooperation, understanding and empathy for the local community that has been going through a lot of very demanding restrictions that they did not choose, but were forced to follow.

"I would like to ask to be sensitive as well to the people who have lost their jobs and loved ones during this horrible time for all of us around the world. I would like to ask all of us to have respect for people who work tirelessly to try to make our lives easier.

"I would like to ask the media to please have consciousness on the impact and influence you bring to this situation and to the community. I would like for the people in the community to know and understand that we have it as our top priority to ensure the health [and] safety of all the people.

"Lastly, I would like for us to please try to support each other as much as someone can or is willing to. Things are always easier when you have a compassionate environment and work together."

Victoria endured tough restrictions after a second coronavirus wave last year.

On Tuesday, the state recorded its 13th consecutive day of no locally acquired cases of COVID-19.

Roberto Bautista Agut labelled the quarantining of players ahead of the Australian Open a "complete disaster", comparing it to prison.

After being exposed to coronavirus on flights to Australia, 72 players are in hotel quarantine for two weeks ahead of the tournament starting on February 8.

Players have hit out at the conditions, although tournament director Craig Tiley insisted on Tuesday most were happy to be in Australia.

But world number 13 Bautista Agut slammed the position players had been put in.

Told he looked like he was in prison, the Spaniard told Sport5: "It's the same, it's the same, with Wi-Fi.

"These people have no idea about tennis, about practice courts, has no idea about anything, so it's a complete disaster because of that, because the control of everything.

"It's not Tennis Australia, it's the people from the government."

Victoria on Tuesday recorded its 13th consecutive day of no locally acquired coronavirus cases, with three of the four in hotel quarantine linked to the Australian Open.

Bautista Agut, a 2019 quarter-finalist at Melbourne Park, said two weeks in quarantine would be difficult.

"I did work in the room but it's not the same," he said.

"I was feeling very, very tight and I cannot imagine staying two weeks like this. It's really, really tough."

Australian Open tournament director Craig Tiley defended Novak Djokovic, saying the world number one had provided "suggestions", not demands.

With 72 players forced into quarantine for two weeks after being exposed to coronavirus on flights, Djokovic reportedly made demands regarding their conditions.

Among them, the eight-time Australian Open champion reportedly asked for players to be moved to private houses with tennis courts, with his requests rejected.

But Tiley played down the reports, saying Djokovic had simply made suggestions.

"Novak wrote a note, these weren't demands, these were suggestions," he told Channel 9 on Tuesday.

"But he too is understanding what two weeks of lockdown means."

Tiley also backed the players despite reports and social media posts suggesting they were unhappy about being forced into quarantine.

"Last night we spent quite a bit of time with the playing group going through a number of different items because they've just been here for a few days getting used to this quarantine environment," he said.

"I have to say on that call there were about 500 players and the vast majority are happy to be here, pleased to be here and really getting ready in the next two weeks to be able to get out and play in the lead-in events and then play the Australian Open on February 8.

"I think the reports we're reading and the things we're seeing doesn't represent the entire playing group. For the most part, they've been pretty good."

With the preparations of 72 players so far impacted by quarantine, there have been suggestions the Australian Open be changed to a best-of-three sets format in the men's draw.

But Tiley said he had no plans to make such a drastic change.

"We're a grand slam at the end of the day and right now three out of five sets for the men and two out of three sets for the women is the position we plan on sticking to, starting February 8," he said.

Nick Kyrgios has labelled Novak Djokovic "a tool" after the world number one reportedly issued a list of demands for players under strict quarantine conditions ahead of the Australian Open.

Defending women's singles champion Sofia Kenin is among 72 players who are consigned to their hotel rooms due to positive coronavirus tests on flights they took to head out for the first grand slam of the year.

Players have posted social media clips of them training and in their rooms, with some complaining about the conditions they are having to contend with for 14 days.

Bernard Tomic's girlfriend, Vanessa Sierra, expressed her grievances over the standard of food and having to wash her own hair and dishes during her period of quarantine with the world number 228 so far.

Djokovic does not have to adhere to such strict rules in Adelaide, where he is due to play in an exhibition tournament before the Melbourne major, as he arrived on a virus-free flight.

Yet the 17-time grand slam champion is said to have asked for less time in isolation for players, requested they are given private housing with access to training courts, and better food.

Kyrgios tweeted on Monday: "Djokovic is a tool. I don't mind Bernie [Tomic] but his Mrs obviously has no perspective, ridiculous scenes Man."

Three weeks before the Australian Open is due to get underway, Victorian premier Daniel Andrews said the players will not be getting any "special treatment."

He said: "The virus doesn't treat you specially, so neither do we.

"I know there's been a bit of chatter from a number of players about the rules.

"The rules apply to them as they apply to everybody else and they were all briefed on that before they came and that was the condition on which they came. So, there's no special treatment here."

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."