Novak Djokovic thanked his fans "around the world" on Friday in his first reaction since being sent to a detention hotel in Australia after his visa was cancelled.
The world men's tennis No.1 has appealed after being refused entry to the country over his vaccination status, ruled as incompatible with Australia's strict COVID-19 requirements.
After being granted a medical exemption to play in the Australian Open later this month, the Australian Border Force rejected his exemption as invalid.
"Thank you to people around the world for your continuous support. I can feel it and it is greatly appreciated," Djokovic posted in English on Instagram.
He also wrote a message in Serbian thanking his family, friends, Serbia, and "good people around the world" who supported him, as well as wishing Orthodox Christians a merry Christmas.
The 34-year-old player, seeking to defend his title in Melbourne and clock up a record 21st Grand Slam title, was sent to a hotel used by immigration officials to house asylum seekers and refugees.
A small group of protesters supporting Novak Djokovic waved flags and banners outside on Friday.
The Australian government has denied reported claims by Djokovic's mother that he is a "prisoner", saying he is free to leave the country at any time.
Father slams treatment at Belgrade rally
The tennis star's treatment has triggered anger among Djokovic’s fans in his native Serbia, with his family calling for protests. Hundreds of Novak Djokovic’s supporters gathered at a rally in downtown Belgrade on Friday.
Speaking at the demonstration, his father Srdjan Djokovic described his son’s struggle to play at the Australian Open as a fight against "globalists who want to ruin everything".
“He is fighting for himself, his people and all freedom-loving nations in the world,” said Srdjan Djokovic, an outspoken critic of the West and supporter of Serbia’s traditional Slavic ally Russia.
“They hate him because Australian politicians have put pressure on people to hate him because he thinks with his own brain.”
The Australian Border Force issued a statement on Thursday, saying it would continue to enforce border laws and entry requirements.
"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," it said.
Australia’s COVID-19 rules say incoming travellers must have had two shots of an approved vaccine or must have an exemption with a genuine medical reason, such as an acute condition, to avoid quarantine.
All players, staff, officials, and fans need to be fully vaccinated against COVID-19 to enter the tournament venue.
Djokovic's stance criticised
Djokovic has said he is opposed to vaccination but had not previously revealed his own status.
His stance has been criticised in the face of scientific evidence that COVID-19 vaccines greatly protect against the virus -- while the vast majority of coronavirus patients in hospital intensive care units are unvaccinated.
A court hearing on Djokovic's bid to stave off deportation is set for Monday, a week before the season's first major tennis tournament is set to begin.
His initial exemption triggered an uproar and allegations of special treatment in Australia, where people spent months in lockdown and endured harsh travel restrictions at the height of the pandemic.
The Australian Border Force said Friday that after further investigations into two other people connected to the Australian Open, one voluntarily left the country and another was taken into detention pending deportation.
The Czech Embassy identified one of them as 38-year-old doubles player Renata Voráčová and said she won't play in the tournament.