Rafael Nadal fended off a battling Emil Ruusuvuori to reach the Melbourne Summer Set final as the Spanish veteran bids to land the 89th singles title of his stellar career.

Nadal, who has won at least one ATP Tour tournament in every season from 2004 onwards, will look to extend that streak into a 19th year after scoring a 6-4 7-5 win on Rod Laver Arena.

He has not captured a title in Australia since 2009, when he landed his only Australian Open triumph to date by beating Roger Federer.

Nadal will be a strong favourite against American qualifier Maxime Cressy in Sunday's final, despite being made to work hard to see out victory over 22-year-old Ruusuvuori.

The 35-year-old Mallorcan looked set for a routine win but dropped serve at 5-3 in the second set, allowing world number 95 Ruusuvuori a path back into the contest.

It provided Nadal with a test of resolve that he came through, tying up victory in an hour and 56 minutes, an encouraging sign as he continues to battle for full sharpness after a near five-month absence.

Nadal acknowledges he may not have long left in tennis, and he wants to make the most of the opportunities that remain.

"I just love what I'm doing," he said in an on-court interview. "I always feel passionate about the sport in general and I feel a very lucky person that I can live from one of my hobbies, tennis.

"I know it's not forever and it's not a job I'm going to do for 50 years, but I want to enjoy it as much as I can while I still have the chance."

The foot injury that caused the 20-time grand slam winner to curtail his 2021 season in August has not prevented him finding winning form this week and now Paris-born Cressy awaits, with the 24-year-old world number 112 enjoying a remarkable week.

Cressy was a 7-5 7-6 (11-9) winner on Saturday against Bulgarian third seed Grigor Dimitrov, serving 17 aces on the way through to his first ATP Tour final.

At the Adelaide International 1 event, Gael Monfils will face Karen Khachanov for the trophy.

Top seed Monfils ended the spirited run of Australian wildcard Thanasi Kokkinakis, earning a 7-5 6-0 semi-final win, while second seed Khachanov battled past former US Open champion Marin Cilic 7-6 (7-3) 6-3.

Novak Djokovic will be "p***ed off" and more determined than ever to win the Australian Open if he is freed from detention on Monday, according to Nick Kyrgios.

The nine-time champion at Melbourne Park had his visa revoked when he arrived in Australia this week, with Border Force officials determining he had "failed to provide appropriate evidence to meet the entry requirements".

He secured an injunction to avoid immediate deportation on Thursday and is spending the weekend at the Park Hotel, also home to refugees and asylum seekers, before his case is heard in court on Monday.

His lawyers have filed a detailed response and called for Djokovic to be liberated, also revealing the 34-year-old Serbian tested positive for COVID-19 on December 16 and has made a full recovery.

Djokovic has a startling 82-8 win-loss career record at the Australian Open and has earned $21,775,855 (US dollars) for his endeavours at the first grand slam of the tennis season.

Should he be cleared to play this time, and successfully defend his title, it would make him the outright leader for men's grand slam titles with 21, nudging him ahead of Rafael Nadal, who is also set to compete, and Roger Federer, who is absent.

Kyrgios has been a fierce critic of Djokovic in the past, but the Australian firebrand this week said the handling of the Belgrade superstar's case had been "really bad" and those taking satisfaction from his situation should "do better".

Having aired those views on social media, Kyrgios expanded on his thoughts in a news conference on Saturday, saying: "For the sport, we need him here.

"I'm feeling for him now, it's not really humane what’s going on. If he's allowed to play the Australian Open, I don't want any bar of him. I reckon he's going to be p***ed off.

"He's going to be very determined to play well and stick it to everyone. And I don't want any bar of that Novak."

Kyrgios claimed media coverage of his comments about Djokovic has "divided us", stating his past remarks have been "blown out of proportion".

In January 2021, Kyrgios described Djokovic as "a tool" after reports he was seeking privileged quarantine restrictions ahead of last year's Australian Open.

Speaking to the No Challenges Remain podcast in 2019, Kyrgios said of Djokovic: "I just feel like he has a sick obsession with wanting to be liked. He just wants to be like Roger [Federer]."

There has been obvious animosity in the past, but this time around Kyrgios is siding with Djokovic. He wants there to be a greater respect shown by Australia towards the world number one.

"I feel he's helped us as well. Like during the bushfires, he was supportive, he was helping us out," Kyrgios said.

"I feel like I could use this as a publicity stunt. I could just agree with the general person and say, 'Yeah, this isn't good', and use it. But I don't think that's right."

Canada will face Spain in their first ATP Cup final after eliminating defending champions Russia in Saturday's semi-final in Sydney. 

Denis Shapovalov and Felix Auger-Aliassime beat Russian duo Daniil Medvedev and Roman Safiullin 4-6 7-5 10-7 in the doubles to complete a tense 2-1 victory for Canada.

World number 14 Shapovalov edged Safiullin 6-4 5-7 6-4, but US Open champion Medvedev levelled up with a 6-4 6-0 win against Auger-Aliassime in the other singles match.

That set up a doubles showdown for the right to face Spain, who overcame Poland on Friday, which Canada came from behind to win.

Russia held in the opening set to take the lead, though a break of serve late in the second set for Canada ensured the contest would be decided by a tie-breaker.

Shapovalov and Auger-Aliassime held their nerve at the Ken Rosewall Arena, recovering from 6-5 down to win 10-7.

It marks a remarkable comeback in more ways than one for Canada, who lost their first four matches of the competition.

"Denis helped me and the team to push myself," Auger-Aliassime said in his on-court interview. 

"We had a tough start in the doubles, so to be able to come back in this way, it's really a team effort.

"That's what the ATP Cup is about. You can still win after being one-all and losing a tough singles. It's really about the team effort and we're happy to be through."

Novak Djokovic tested positive for COVID-19 in December and was later given the go-ahead by Australia's Department of Home Affairs to travel to Melbourne, his lawyers said on Saturday.

The men's tennis world number one is being detained at the Park Hotel in Melbourne ahead of a court hearing on Monday that should determine whether he is allowed to stay in Australia.

The Australian Open begins on January 17 and Djokovic's legal team are battling for him to be freed in order to prepare for and participate in the tournament.

Australian Border Force officials cancelled his visa application on Thursday, stating Djokovic had "failed to provide appropriate evidence to meet the entry requirements to Australia".

Djokovic had been granted a medical exemption by organisers of the first grand slam of the year, but his fate now hangs in the balance.

His lawyers filed a detailed submission to the Federal Circuit and Family Court of Australia on Saturday, in which it was stated that Djokovic was granted a temporary activity visa on November 18.

This did not contain any conditions regarding his vaccination status, lawyers for Djokovic said, adding that the Serbian then tested positive for coronavirus, after a PCR check, on December 16. This was confirmed by the Institute of Public Health of Serbia, the 34-year-old's lawyers said.

Subsequently, having recovered from COVID-19, Djokovic was informed he was eligible to play the first grand slam of 2022 by Tennis Australia officials.

According to details filed by his lawyers, Djokovic received confirmation on December 30 from Tennis Australia's chief medical officer that he had been awarded a medical exemption to compete, on the basis he had recently recovered from the virus.

"Mr Djokovic had also received, on 01 January 2022, a document from the Department of Home Affairs in regard to his Australian Travel Declaration," his lawyers said.

This document, according to his representatives, stated that Djokovic was informed "[his] responses indicate[d] that [he met] the requirements for a quarantine-free arrival into Australia where permitted by the jurisdiction of your arrival".

If cleared to leave his hotel and compete in the Australian Open, Djokovic will be seeking a 10th title at Melbourne Park and a 21st grand slam. He currently shares the men's record of 20 major titles with Roger Federer and Rafael Nadal.

Novak Djokovic thanked the supporters campaigning for him to be allowed to play at the Australian Open as he spoke out for the first time since being detained in Melbourne.

The ATP world number one will spend the weekend in a hotel that also houses refugees and asylum seekers, some of whom have been waiting years for the chance of freedom.

A court hearing on Monday should determine Djokovic's fate after Border Force officials cancelled his visa application, stating the 34-year-old had "failed to provide appropriate evidence to meet the entry requirements to Australia".

Djokovic seemed all set to play after he was granted a medical exemption by organisers of the first grand slam of the year, but his fate now hangs in the balance. An injunction secured by his legal team has allowed him to remain in the country for now, albeit in detention.

The Serbian superstar wrote on Instagram: "Thank you to people around the world for your continuous support. I can feel it and it is greatly appreciated."

That came after a message from Djokovic to mark Orthodox Christmas on Friday, as he wrote: "Peace of God. Christ was born. Merry Christmas. May God's love strengthen and fulfil you."

The Australian Open begins on January 17 and this is just about the worst possible preparation for the 20-time major winner, even if he is given permission to remain in Australia at Monday's hearing.

There was an outcry from many Melburnians when Djokovic announced on Tuesday that he was on his way to the tournament with an exemption pass.

A small number have since protested that Djokovic should be liberated, while he has found some support on social media and extensive backing from his homeland, with Serbian president Aleksandar Vucic accusing Australian authorities of "harassment of the best tennis player in the world", pledging to "fight for Novak Djokovic, for justice and truth".

Djokovic is a record nine-time champion at Melbourne Park, but there is said to be a strong feeling locally that he should have to show proof of being vaccinated against COVID-19, given the efforts residents have gone to and the stringent restrictions imposed on them during the pandemic to date.

Australian Open officials have claimed "rigorous" checks were put in place to assess the veracity of any claim for an exemption.

One theory that has been widely suggested is Djokovic, who has spoken out about vaccine matters in the past, may have been awarded the exemption on the basis he had a positive test for COVID-19 in the past six months. He has not publicly confirmed he has recently had the virus.

However, reports from Australia have stated federal government officials instructed Tennis Australia in recent months that experiencing a recent case of coronavirus was not an adequate explanation for a player not being fully vaccinated.

Djokovic's wife, Jelena, issued a statement in support of her husband, posting on Instagram: "We wish we are all together today, but my consolation is that at least we are healthy. And we will grow from this experience.

"Thank you dear people, all around the world for using your voice to send love to my husband. I am taking a deep breath to calm down and find gratitude (and understanding) in this moment for all that is happening.

"The only law that we should all respect across every single border is love and respect for another human being. Love and forgiveness is never a mistake but a powerful force."

Australian authorities, all the way up to prime minister Scott Morrison, have contended their border laws are there for a good reason, with Monday promising to be a seismic day in the capital of Victoria.

Rafael Nadal was handed a walkover to the semi-finals of the Melbourne Summer Set tournament when his opponent withdrew with a foot injury.

In an ironic development, given Nadal has been so plagued by his own serious foot problems, Tallon Griekspoor had to pull out of his scheduled clash with the 20-time grand slam champion on Friday.

That was perhaps not the news Nadal wanted, given the Spaniard is competing this week to gain much-needed match practice ahead of the Australian Open. It is his first ATP Tour event since August, when a long-existing left foot problem caused him to curtail his season.

Withdrawing from a Rod Laver Arena tussle with Nadal was a painful blow to 25-year-old Dutchman Griekspoor too, and he wrote on Twitter: "These are the matches you play for."

It would have been a first career meeting with all-time great Nadal for the world number 65, who instead faces a fitness battle before the first grand slam of the year begins on January 17.

Nadal will go on to face Finland's Emil Ruusuvuori, who won 6-2 6-1 against Slovakian Alex Molcan. The other semi-final on Saturday will see Bulgarian third seed Grigor Dimitrov tackle American qualifier Maxime Cressy.

At the Adelaide International, the top three seeds sauntered through to the semi-finals. Top seed Gael Monfils brushed aside Tommy Paul 6-4 6-1, number two Karen Khachanov saw off Egor Gerasimov 7-5 6-3, and third seed Marin Cilic was a 6-3 6-2 winner over Laslo Djere.

It was also confirmed on Friday that former world number one Andy Murray has been awarded a wildcard into next week's Sydney Classic.

Murray suffered a first-round exit in Melbourne and is looking for a run of matches before launching his campaign at the Australian Open, where he is a five-time runner-up.

Roberto Bautista Agut saw Spain through to a second ATP Cup final by beating Hubert Hurkacz after Pablo Carreno Busta outclassed Jan Zielinski in Sydney on Friday.

Bautista Agut made it mission accomplished for Spain by defeating Poland's world number nine 7-6 (8-6) 2-6 7-6 (7-5) at the Ken Rosewall Arena.

Spain were beaten by Serbia in the final two years ago, but will get another opportunity to lift the trophy on Sunday when they face Canada or Russia.

Bautista Agut has won all four matches he has played in the competitions this week and came out on top despite Hurkacz hitting 61 winners to his 28.

The 33-year-old only made 14 unforced errors and secured the only mini-break in a final-set tie-break to put Spain into the final once again.

He said: "It's a match that I will always remember. I think both of us could get the win today. He also really deserved a lot of good things. But this is our game, this is tennis.

"Today I was the one who got the win. I think I also deserved it. I did a lot of good things on the court."

Novak Djokovic has been warned by Boris Becker that his "stubbornness" could prevent him being remembered as the greatest tennis player that ever lived.

World number one Djokovic, who has not declared his COVID-19 vaccination status, seemed set to play in this month's Australian Open after he was granted a medical exemption by tournament organisers.

That was required for any player who has not been fully vaccinated. One theory that has been widely suggested is that Djokovic may have been entitled to an exemption after a positive test for COVID-19 in the past six months, although he has not confirmed he has recently had the virus.

However, Djokovic is now set to spend the weekend in a Melbourne detention hotel in which refugees and asylum seekers are also being kept, after Australian Border Force's decision to cancel his visa application.

A court hearing on Monday should provide a resolution to the saga, with Djokovic's legal team set to battle for his right to enter the country and play in the season's first grand slam, at which he would be bidding to win a record 21st men's singles major title. The Australian Open gets under way on January 17.

Becker coached Djokovic for three seasons, from 2014 to 2016, and told the Daily Mail the 34-year-old Serbian is "making a big mistake in not getting vaccinated".

The German said the decision "is one that threatens what remains of his career and his chance to cement himself as the greatest player of all time".

Becker, a six-time grand slam winner, said: "The same incredible determination which I saw win so many close matches can be a vulnerability with his stubbornness.

"It is not just about Australia. The fact is that we are living in a different world and he is going to find it very hard to live the life of a professional tennis player travelling around without the vaccination.

"Maybe one day we will get back to a more normal situation, but at 34 he does not have much time left to pursue his goals."

There have been protests on the streets of Melbourne and Belgrade, with arrests made by police in the Victorian capital, while Djokovic found some support from within the tennis fraternity on Friday, as American John Isner backed his case.

Isner wrote on Twitter: "What Novak is going through right now is not right. There’s no justification for the treatment he’s receiving. He followed the rules, was allowed to enter Australia, and now he’s being detained against his own will. This is such a shame. #IStandWithNovak".

Nick Kyrgios, who has had his run-ins with Djokovic in the past, labelled Australia's handling of the situation "really bad", while former world number one Andy Roddick also appears to be in Djokovic's corner.

Yet Australia's home affairs minister Karen Andrews rejected any idea that Djokovic was being "held captive".

Andrews told the ABC: "Can I say, firstly, that Mr Djokovic is not being held captive in Australia. He is free to leave at any time that he chooses to do so and Border Force will actually facilitate that.

"Yes, there was a visa issued – that is actually not the issue. It is the second part of that process, which is the specific entry requirements to be able to cross Australia's border and to enter Australia lawfully."

She said Djokovic was not the only tennis case that was under investigation by Australian authorities. A player and an official are reported to be under scrutiny.

"I'm aware of investigations in relation to two individuals by the Australian Border Force," Andrews said. "They're going through their processes of investigation.

"And at some time, they will brief me, but all I can absolutely assure you and the rest of Australia of is that the Australian Border Force will take absolutely the appropriate action."

The Professional Tennis Players Association (PTPA) has issued an update on Novak Djokovic, expressing their view that he should be allowed to compete at the Australian Open with an approved medical exemption.

World number one Djokovic, who has not declared his COVID-19 vaccination status, seemed set to play in the year's opening major, which he has won nine times previously, after he confirmed he had received a medical exemption to compete.

Protocols in Australia require proof that players have been vaccinated or have a medical exemption to compete at Melbourne Park.

Tournament director Craig Tiley insisted that the 20-time major champion had not been given a "special favour" to play in the tournament, though the decision faced immediate and widespread backlash and on Wednesday, Djokovic's visa application was cancelled.

However, the Serbian's legal team filed for a judicial review, with the case to be heard by Federal Circuit Court Judge Anthony Kelly on Monday at 10am local time in Melbourne.

Djokovic is now hauled up in a Melbourne hotel, and cannot be deported until the hearing has taken place unless he leaves the country of his own volition.

Protestors have also appeared outside of the hotel where Djokovic has been transferred, while Nick Kyrgios has expressed his displeasure at the way the situation has been handled.

The matter has also drawn criticism from Serbia's president Aleksandar Vucic, who labelled Australia's treatment of the nation's superstar as "harassment."

On Friday, the PTPA - which was founded by Djokovic and Canadian player Vasek Pospisil in 2020 - issued an update on the situation.

The PTPA has been diligently monitoring the detainment of professional tennis player Novak Djokovic by the Australian Government.

"The PTPA has been in close contact with Mr Djokovic, his family and legal counsel, government officials and Australian Open leadership," a statement read.

"Mr Djokovic has verified his well-being to us. He has also requested that we allow him to personally share the facts of his detainment in his own words, and in his own time.

"With the utmost respect for all personal views on vaccinations, vaccinated athletes and unvaccinated athletes (with an approved medical exemption) should both be afforded the freedom to compete. We will continue to support and advocate for our members, and all players, in a manner that is acceptable to them."

The statement concluded with: "We will continue to monitor his health, safety and well-being. We look forward to his time back on the court."

Nick Kyrgios has labelled the reaction to and handling of Novak Djokovic's predicament as "really bad".

Djokovic faces deportation from Australia after having had his visa application cancelled.

The world number one has not revealed his vaccination status against COVID-19, but was set to compete at the Australian Open under a medical exemption.

That decision called uproar in Australia, which has been under strict lockdown restrictions for much of the pandemic.

However, Djokovic was denied entry into Australia upon his arrival at Melbourne airport, with Australian Prime Minister Scott Morrison saying the 20-time grand slam champion would be on "the next plane home" if he failed to produce a sufficient reason for his medical exemption.

Australian Open tournament director Craig Tiley insisted that the 20-time major champion had not been given a "special favour" to play in the tournament, though the decision faced immediate and widespread backlash.

Djokovic is currently hauled up in a hotel after an interim injunction hearing was pushed back to Monday at 10am local time, with Federal Circuit Court Judge Anthony Kelly ruling that the Serbian could not be deported until at least 4pm on Monday, local time.

Several of Djokovic's fellow players, including Rafael Nadal, have criticised the 34-year-old's stance and the decision to initially allow him to compete.

Yet Kyrgios, who has never seen eye to eye with Djokovic, has not joined those critics, and instead hit out at how Australia, and the media, have handled the situation.

"Look I definitely believe in taking action, I got vaccinated because of others and for my mum's health, but how we are handling Novak’s situation is bad, really bad," Kyrgios tweeted on Friday.

"Like these memes, headlines, this is one of our great champions but at the end of the day, he is human. Do better."

Kyrgios said in November that he believed the Australian Open should be cancelled if it was mandated that competitors would have to be vaccinated.

 "I don't think the Aus Open should go ahead, just for the people in Melbourne – you’ve got to send a message," Kyrgios said on his 'No Boundaries' podcast at the time.

Felix Auger-Aliassime pulled off a terrific win over Alexander Zverev to carry Canada through to the ATP Cup semi-finals.

After Great Britain beat the United States 2-1 earlier to stake a claim for a last-four spot, Canada's singles players rose to the challenge to see off Germany.

That meant disappointment for Dan Evans and the British team, with Canada progressing to a clash with Russia as winners of Group C.

Denis Shapovalov got the better of Jan-Lennard Struff in a tight tussle, the world number 14 beating 51st-ranked Struff 7-6 (7-5) 4-6 6-3, giving Auger-Aliassime a swing at Olympic Games and ATP Finals champion Zverev before a possible doubles decider.

The world number 11 duly got the better of third-ranked Zverev by a similar score to the opening singles rubber, winning 75 per cent of first-serve points as he came through 6-4 4-6 6-3 late at night in Sydney.

Great Britain had impressed in edging out the US team, with Dan Evans beating John Isner and then teaming up with Jamie Murray to see off Isner and Taylor Fritz 6-7 (3-7) 7-5 10-8 in a dramatic doubles decider. Fritz beat Cameron Norrie in the second singles rubber.

Daniil Medvedev played a pivotal role as Russia wrapped up a perfect 3-0 match record in Group B, beating Italy 2-1 to nail down their semi-final place.

Defending champions Russia, who also won the Davis Cup last year, were on the back foot early on against Italy after Jannik Sinner beat Roman Safiullin, but US Open champion Medvedev ground out a 6-2 6-7 (5-7) 6-4 win over Matteo Berrettini to take the match – and the battle for top spot in the group – down to a doubles decider.

Medvedev and Safiullin were given a stiff test by their singles foes on the doubles court but had just enough to beat Berrettini and Sinner 7-5 4-6 10-5.

Rafael Nadal declared his first singles match on the ATP Tour for five months a roaring success after the Spaniard battled past Ricardas Berankis in Melbourne.

A 6-2 7-5 win for Nadal over the Lithuanian qualifier carried the 35-year-old into the quarter-finals of the Melbourne Summer Set tournament.

Playing on Rod Laver Arena, the main show court for the upcoming Australian Open, top seed Nadal was tested by Berankis but came through unscathed, breaking serve to love to clinch the victory.

This was the first time that Nadal had faced Berankis, the world number 104 who briefly entered the top 50 five years ago, and it came as the 20-time grand slam winner battles back from the left foot injury that curtailed his 2021 season.

Nadal had not competed on tour since losing to Lloyd Harris in the third round in Washington in August, and the match practice he gained at an exhibition event in Abu Dhabi last month was followed by him contracting COVID-19.

He is vaccinated though, so was able to travel once he recovered from that brush with coronavirus, and is looking to build up form and fitness before the Australian Open begins.

"Honestly, I've been going through some difficult, challenging moments the last year and a half, but in general terms I'm super happy to be back in competition," Nadal said.

"It's important to start with a victory. It gives me the chance to play another time tomorrow and that's the main thing at this moment because I didn't play for such a long time.

"The main thing is being healthy. That's probably the only thing."

Awaiting Nadal in the last-eight stage will be Dutch player Tallon Griekspoor, who fended off Australia's Alexei Popyrin in three sets.

Determined not to take on too heavy a workload, Nadal has pulled out of the doubles tournament, despite making a winning start on Tuesday when he paired up with fellow Spaniard Jaume Munar.

He elected to play doubles initially to build up some rhythm. "In doubles, things always happen fast," Nadal said. "It makes you feel alive on the tour again. I think that was a positive thing."

Third seed Grigor Dimitrov advanced, seeing off Andy Murray's conqueror Facundo Bagnis in three sets, but Belgian fourth seed David Goffin slumped to a 7-5 6-3 loss against Slovakian Alex Molcan.

At the Adelaide International 1 tournament, there were wins at the last-16 stage for the top three seeds – Gael Monfils, Karen Khachanov and Marin Cilic – but fourth seed Frances Tiafoe was caught out by Australian Thanasi Kokkinakis, losing in three sets.

Novak Djokovic will remain in Australia until at least Monday, when a hearing on his appeal against deportation will take place.

World number one Djokovic, who has not declared his COVID-19 vaccination status, seemed set to play in this month's Australian Open after he was granted a medical exemption.

Protocols in Australia require proof that competitors and staff have been jabbed or have a medical exemption to compete at Melbourne Park.

Tournament director Craig Tiley insisted that the 20-time major champion had not been given a "special favour" to play in the tournament, though the decision faced immediate and widespread backlash.

On Wednesday, Djokovic faced deportation after Australian Border Force's decision to cancel his visa application, with Prime Minister Scott Morrison declaring "rules are rules."

However, the Serbian's legal team have filed for a judicial review, with the case to be heard by Federal Circuit Court Judge Anthony Kelly on Monday at 10am local time in Melbourne.

Due to a delay in receiving the application for a review of the visa decision and the temporary ban on Djokovic's deportation, it has been agreed that the 34-year-old should remain in Australia until at least Monday. 

Djokovic can leave Australia of his own volition. 

Protestors have also appeared outside of the hotel where Djokovic has been transferred, supporting the nine-time Australian Open winner.

The matter has also drawn criticism from Serbia's president Aleksandar Vucic, who labelled Australia's treatment of the nation's superstar as "harassment." 

Rafael Nadal, meanwhile, suggested Djokovic had made life difficult for himself by refusing to reveal his vaccination status.

"The only thing that I can say is I believe in what the people who know about medicine says, and if the people say that we need to get vaccinated, we need to get the vaccine," Nadal said.

"I went through COVID. I have been vaccinated twice. If you do this, you don't have any problem to play here. The world in my opinion has been suffering enough to not follow the rules.

"I think if he wanted, he would be playing here in Australia without a problem. He made his own decisions, and everybody is free to take their own decisions, but then there are some consequences."

The Australian Open starts on January 17.

Rafael Nadal declared it was imperative to "follow the rules" on COVID-19 vaccinations after rival Novak Djokovic was told he faces being deported from Australia.

World number one Djokovic was left fighting for the right to compete at the Australian Open, a tournament he has won nine times, after authorities cancelled his visa.

A medical exemption was expected to allow Djokovic to enter the country, regardless of his vaccination status, which he has yet to formally disclose.

However, the Australian Border Force declared the Serbian had been ordered to fly out of the country on Thursday, sparking a challenge to that decision by Djokovic's legal team.

Reports in Australia said an interim injunction had been granted, meaning Djokovic will remain in immigration detention until a court hearing on Monday.

According to Nadal, who had COVID-19 recently but has been cleared to compete at Melbourne Park, Djokovic would have made his life a lot easier by going down the vaccination route.

"It's normal that the people here in Australia get very frustrated with the case because they have been going through a lot of very hard lockdowns, and a lot of people were not able to come back home," Nadal said.

"The only thing that I can say is I believe in what the people who know about medicine says, and if the people say that we need to get vaccinated, we need to get the vaccine.

"I went through COVID. I have been vaccinated twice. If you do this, you don't have any problem to play here. The world in my opinion has been suffering enough to not follow the rules.

"I think if he wanted, he would be playing here in Australia without a problem. He made his own decisions, and everybody is free to take their own decisions, but then there are some consequences."

Djokovic was initially detained at an airport after arriving in Australia, while his status remained in limbo. His coach, Goran Ivanisevic, said it had been "not the most usual trip Down Under".

Spanish superstar Nadal has 20 grand slam titles, the same number that Djokovic and Roger Federer have brought up across their careers. They are locked in a race to finish with the most majors, and Federer, at 40, is battling back from injury and unlikely to compete at a slam before the US Open.

Australia's Prime Minister Scott Morrison tweeted on Thursday: "Mr Djokovic's visa has been cancelled. Rules are rules, especially when it comes to our borders.

"No one is above these rules. Our strong border policies have been critical to Australia having one of the lowest death rates in the world from COVID, we are continuing to be vigilant."

Nadal has some sympathy for Djokovic, but it appears to be limited.

"Of course, I don't like the situation that is happening," Nadal said. "In some way I feel sorry for him. But at the same time, he knew the conditions since a lot of months ago, so he makes his own decision."

Novak Djokovic was left fighting for the right to compete at the Australian Open on Wednesday after authorities cancelled his visa.

The world number one announced on Tuesday that he had received a medical exemption to play in the tournament he has won a record nine times. 

That medical exemption was expected to allow Djokovic to enter the country, regardless of his vaccination status, which he has yet to formally disclose.

However, the Victorian government reportedly rejected an application as a member of Djokovic's support team made an error in requesting a sub-class of visa.

Further doubt was cast over Djokovic's chances of being allowed to contest the first grand slam of the year when Jaala Pulford, the acting sports minister of the state of Victoria, later declared on social media that the Serbian's application will not be supported.

It was later announced by the Australian Border Force (ABF) he had been ordered to fly out of the country on Thursday, although his legal team was said to be challenging the decision.

"The ABF can confirm that Mr Djokovic failed to provide appropriate evidence to meet the entry requirements to Australia, and his visa has been subsequently cancelled," the force said.

"Non-citizens who do not hold a valid visa on entry or who have had their visa cancelled will be detained and removed from Australia.

"The ABF can confirm Mr Djokovic had access to his phone.​"

Djokovic's father had earlier accused authorities of holding the 20-time major winner "captive for five hours".

He told Russian news agency Sputnik: "This is a fight for the libertarian world, not just a fight for Novak, but a fight for the whole world.

"If they don't let him go in half an hour, we will gather on the street. This is a fight for everyone."