Novak Djokovic secured a Covid-19 vaccine exemption from Tennis Australia and the Australian government because he had tested positive for the virus in December, which should have qualified him for entry into the country, his lawyers argued Saturday.

"The date of the first positive Covid PCR test was recorded on 16 December 2021," his legal team said in a 32-page submission ahead of a federal court hearing Monday to appeal the decision to cancel the Serbian star's visa.

In another twist to the saga which has reverberated around the world, pictures shared by the Belgrade tennis federation showed Djokovic at a young players event in the city on December 17.

The federation reported in a statement that Djokovic had handed over cups and prizes to the best young players. No one was wearing a mask.

The vaccine-sceptic tennis ace was detained on arrival in Australia earlier this week
The vaccine-sceptic tennis ace was detained on arrival in Australia earlier this week AFP / Marco BERTORELLO

Djokovic had also attended another gathering on December 16, when the Serbia national postal service honoured him by launching a series of stamps featuring him and his sports achievements.

On Saturday, his lawyers claimed that Australian border agents held Djokovic for eight hours at Melbourne airport, mostly incommunicado, before cancelling his visa and sending him to a detention centre.

After landing in Melbourne Wednesday night, the 34-year-old -- who had first tested positive for Covid in June 2020 -- had asked for time to rest and consult his legal team the following morning.

But after a border official initially agreed, his superiors successfully pressured Djokovic to allow them to take an immediate decision on his visa, the lawyers said.

In a series of fiery remarks, Srdjan Djokovic told a crowd in Belgrade that his son was the victim of a "political witch hunt"
In a series of fiery remarks, Srdjan Djokovic told a crowd in Belgrade that his son was the victim of a "political witch hunt" AFP / ANDREJ ISAKOVIC

Foreigners are still mostly banned from travel to Australia, and those granted entry must be fully vaccinated or have a medical exemption.

Djokovic also asked Saturday to be allowed to leave the Melbourne detention centre where he was moved on Thursday so that he can train ahead of the Australian Open.

Although Djokovic has won a legal reprieve from deportation, it is unclear whether he will be able to play in the January 17-30 Australian Open.

If successful, he will be gunning for a 10th Australian Open crown and a record 21st Grand Slam title -- a milestone that Spanish great Rafael Nadal is also chasing.

Refugee advocates are protesting outside a Melbourne detention centre where tennis champion Novak Djokovic is reported to be staying
Refugee advocates are protesting outside a Melbourne detention centre where tennis champion Novak Djokovic is reported to be staying AFP / William WEST

In an internal video leaked Saturday, Tennis Australia chief Craig Tiley said his organisation had done "everything they possibly could".

"There is a lot... of blaming going on but I can assure you our team has done an unbelievable job," he said in a video published by the Sunday Herald Sun newspaper.

A second tennis player who was headed to the tournament -- Czech doubles specialist Renata Voracova -- had her visa cancelled after initially being allowed into the country, her government has confirmed.

She was also placed in the Melbourne centre and told Czech media the facility was "a bit like in prison".

Melbourne's 'alternative place of detention' houses about 32 migrants trapped in Australia's hardline immigration system
Melbourne's 'alternative place of detention' houses about 32 migrants trapped in Australia's hardline immigration system AFP / CON CHRONIS

An Australian government source Saturday said Voracova had flown out of Australia. AFP photo and video images earlier showed a woman who appeared to be Voracova in a vehicle leaving the centre.

Djokovic, an outspoken vaccine sceptic, has thanked fans around the world for their support on Instagram: "I can feel it and it is greatly appreciated."

More than 100 supporters and anti-vaccine protesters rallied outside the Melbourne immigration holding facility Saturday, banging drums and chanting "Novak".

There was also support for Djokovic at an anti-vaccine rally attended by hundreds of people in another part of the city.

"I don't want to see my grandchildren vaccinated," said Margaret Beacham, a 67-year-old former primary school teacher.

"Novak is making a stand and it's a worldwide opportunity for him to say something about vaccination status and how ridiculous it is."

As much of the country tightened restrictions to battle an Omicron-fuelled wave, the state of Victoria, where Melbourne is the capital, posted a daily record of 51,356 cases Saturday.

The centre holding Djokovic, previously the Park Hotel and officially known as an "alternative place of detention", houses about 32 migrants trapped in Australia's hardline immigration system -- some for years.

Nobody is allowed in or out except staff.

The five-storey centre gained notoriety last year when a fire forced migrants to be evacuated, and maggots were allegedly found in the food.

Djokovic's family have said the hotel is "dirty".

Djokovic's detention has sparked international scrutiny, with the Serbian government demanding explanations.

"Djokovic is not a criminal, terrorist or illegal migrant, but was treated that way by the Australian authorities, which causes an understandable indignation of his fans and citizens of Serbia," the foreign ministry said.

Australian Prime Minister Scott Morrison has defended revoking Djokovic's visa.

"Rules are rules," he said.

"The tail won't be wagging the dog here," he said.