Novak Djokovic may be ordered to leave Australia a day after his arrival for the Australian Open.

Border officials detained the top-ranked men’s player at Melbourne Airport for eight hours Wednesday. The star tennis player, who has repeatedly declined to disclose his vaccine status, received a medical exemption from the tournament to compete. His status is now in doubt, though he plans to challenge the country’s ruling.

It likely won’t work — and his attempt at a 10th Australian Open title is in jeopardy.

“Mr Djokovic’s visa has been cancelled,” Australian prime minister Scott Morrison tweeted Wednesday. “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.”

Per Australian media, Djokovic’s team applied for a visa that does not apply to those who have received medical exemptions for the COVID-19 vaccine. The Age reported officials deemed the defending Australian Open champion had failed to demonstrate sufficient evidence he qualified for the vaccine exemption. The BBC added that Australia plans to deport the tennis star.

“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 Australian Border Force said in a statement to The Age.

Djokovic, who has repeatedly declined to disclose his vaccine status, received a medical exemption from the Australian Open to compete in the tournament. He has won the major nine times, including the last three years.

The top-ranked men’s player was being guarded by police and held “in a room which no one can enter,” at the airport, according to Djokovic’s father, Srdjan.

“I have no idea what is happening, they are holding my son in captivity for five hours,” Srdjan told Serbian news outlet B92.

Serbian president Aleksandar Vucic said on Instagram that he’d spoken to Djokovic, adding Serbian authorities were taking measures “so the harassment of the best tennis player in the world be stopped in the shortest possible time.”

Throughout the pandemic, Australia has had some of the most severe COVID-19 restrictions in the world and government officials seemed prepared for Djokovic’s arrival.

“They have provided [Djokovic] with an exemption to come to Australia, and so we then act in accordance with that,” Morrison said this week. “States provide exemptions for people to enter on those basis, and that’s been happening for the last two years.

“And so if medical exemptions had been provided by medical professionals and that’s been furnished to him as a proviso for him to get on that plane, well, that will have to stack up when he arrives in Australia.”

Djokovic is tied with Rafael Nadal and Roger Federer for the most career major titles. All three have won 20.