Djokovic court case: Could he argue his way to the Open?

The world number one men's tennis player will spend this weekend stewing in a hotel room in Australia, fighting the country's attempt to deport him over his vaccination status.

Then on Monday, Novak Djokovic will get his day in court to challenge the cancellation of his visa. He wants to get into the country to play in the Australian Open and win his 10th title.

How will he argue his case and how strong are his prospects? Will he be able to make it to the Grand Slam at all, let alone on time?

The Serbian player was granted a visa to enter Australia on proviso, to play in the Grand Slam.

Because Australia still has Covid rules banning most foreigners from entering the country, Djokovic applied for a "temporary activity" visa, which allows foreigners in for major events. Most of the players competing in the tournament are entering on this visa.

Australia's pandemic border rules also ban foreigners from entering the country if they are not either double vaccinated or have a medical exemption from having the jabs.

Djokovic, who has said he is opposed to vaccination, had been granted by tennis authorities a medical exemption to play in the tournament, endorsed by the Victorian state government - which his lawyers say was on the basis that he had a bout of Covid confirmed by a PCR test on 16 December.

But upon arrival at Melbourne Airport, the tennis player's visa was apparently cancelled by border officials who said that under federal rules a prior infection was not a valid reason to enter without a vaccination.

"All I can say is that the evidence for medical exemption that was provided was found to be insufficient," Prime Minister Scott Morrison told reporters on Thursday.

After eight hours at immigration control, as he no longer had a legal basis to be in Australia, Djokovic was then moved to a holding zone to be deported. He is spending the weekend in an immigration detention hotel that has often been criticised by refugees for its poor conditions

The player's team immediately challenged the decision and on Thursday he was granted a temporary injunction to stave off being forcibly flown out that night.

In court documents released on Saturday, Djokovic's lawyers say the tennis star had every reason to believe he was entitled to travel to Australia and play in the tournament - and alongside his visa he had a document from the Department of Home Affairs saying his travel declaration had been assessed and he met the requirements for quarantine-free arrival.

The legal documents outline a complicated series of arguments that make reference to laws like the Biosecurity Act and the Migration Act governing arrivals into Australia.

But when the case comes to court on Monday, it appears that Djokovic's lawyers will effectively say that the decision to revoke the visa was affected by a variety of "jurisdictional errors".

They will argue that the correct procedures were not followed in revoking the document - for example questioning whether the player was properly informed of the move to cancel the visa and whether he was given the correct legal opportunity to respond.

Another key argument will be over whether border officials misconstrued the guidance around what constituted a medical reason not to be vaccinated, the documents suggest.

Professor Donald Rothwell, an international law expert from the Australian National University, told the BBC that "any revocation of the visa requires justification... and there are certain legal processes that need to be followed for the visa to be revoked."

Foreigners can fly in to Australia on a visa they applied for online - but when they get to the airport they have to clear immigration customs.

If they're caught out on a visa error, they're restricted in their appeal scope, Professor Mary Crock, an immigration law expert from the University of Sydney, told the BBC.

"When he goes to court, he can't say: 'Look at me, I'm the number one player in the world I should be let in and allowed to play!' No. None of that, none of those issues of merit apply," she said.

Mr Morrison has rejected all accusations, including from Serbia's government, that Australia unfairly targeted Djokovic.

"This is a very specific case that deals with one individual, Australia's sovereign border laws, and their fair application," he said on Thursday.

He added that Australian border officials act on what they know, and that those who, like Djokovic, broadcast their pending entry into Australia on social media, "draw significant attention to themselves".

Australia initially allowed several other Grand Slam participants to enter with medical exemptions, but their visas are now also under scrutiny.

Djokovic's team will likely also try to argue that the decision was unreasonable, because the issue was broadcast well in advance, Prof Crock said.

"This guy is so high profile- he's the number one in the world. Everyone knew he was coming and I don't think it's acceptable for the federal government to turn around and say we didn't know any of this until he arrived in Australia," she said.

"They absolutely did. And they let him get on the plane."

Prof Crock said Djokovic's team might also reference the political circus, in an attempt to argue political influence, which would be a breach of legal decision making.

"This has been a case of extraordinarily high political value. Accordingly one of the grounds could well be that they'll argue the decision maker [border official] was acting under the influence or dictation of the prime minister. But in saying that, that's an extraordinarily difficult ground to make out," she said.

There's also been no evidence so far of any sort of heavy-handed direction like that from the government.

If the judge were to find in favour of the tennis player, a best-case scenario for Djokovic would be the court overturning Australia's revocation of his visa.

That would allow him to enter the country immediately, with a week more remaining to prepare for the Grand Slam.

It's unclear whether the Australian government would challenge the decision, attempt to cancel the visa on other grounds, or back down.

He might not be deported immediately. Djokovic's team could apply to challenge the decision again in an appeal court.

But would that be worth it for the tennis player? He will have had no tennis practice for a full fortnight, and would likely have to endure more time in hotel detention. There are already efforts being made by Serbian officials to move him to a nicer hotel.

The legal experts say it will take at least a week for a higher court to be convened for the appeal hearing, by which time the tournament will have already begun.

"If he loses, the timeframe - even under the most extreme scenario - of him being able to compete in the Open just seems impossible really," Prof Rockwell said.