Tennis world number one Novak Djokovic spent Orthodox Christmas in Australian immigration detention on Friday as his lawyers fight a government decision to remove him from the country that could scupper his shot at a record-breaking 21st Grand Slam.
As the row escalated, officials said two other players who entered the country under the same exemptioninitially granted to Djokovic were under investigation.
Border officials detained Djokovic at Melbourne's airport when he arrived on Wednesday evening and revoked the visa he had been granted on the basis of a medical exemption from Australia's strict COVID-19 vaccination requirements.
The initial decision to grant entry to Djokovic was met with outrage in Australia, a country with an adult vaccination rate of more than 90% that is battling its worst surgeof coronavirus infections.
The Australian government pushed back on Friday against suggestions by Serbian supporters, including Djokovic's family, that the star player was effectively a prisoner, stressing he is free to leave the country at any time.
"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," Home Affairs Minister Karen Andrews told reporters.
Djokovic's lawyers successfully scrambled for urgent legal approval for him to remain in the country until a full court hearing in his case against the federal government on Monday.
The public hearing is expected to reveal more details about the exemption granted to Djokovic and the documentation he provided to immigration officials at the border to support it.
The 34-year-old has not revealed the grounds for the exemption and has consistently refused to disclose his vaccination status, while publicly criticising mandatory vaccines.
Vaccines are not mandatory in Australia but they are required for a range of activities.
As he was confined for a second day to his room in the modest Park Hotel, where several Afghan immigration detainees have been held for months, Djokovic's plight was met with a mixed response from his rivals in elite tennis.
Former World number one and two-time Australian Open champion Boris Becker said Djokovic was "making a big mistake" with his anti-vaccination stance.
"It is one that threatens what remains of his career and his chance to cement himself as the greatest player of all time," Becker wrote in an opinion piece in The Daily Mail newspaper.
Spanish champion Rafael Nadal told reporters in Melbourne he felt sorry for his rival "but at the same time, he knew the conditions since a lot of months ago."
However, American tennis player Tennys Sandgren sent his support.
"Novak, stay strong, buddy," Sandgren told Reuters. "Hope you get out of there soon."