Novak Djokovic of Serbia plays a backhand against Marin Cilic of Croatia during the Davis Cup Semi Final match between Croatia and Serbia at Madrid Arena pavilion in December in Madrid, Spain.

Novak Djokovic of Serbia plays a backhand against Marin Cilic of Croatia during the Davis Cup Semi Final match between Croatia and Serbia at Madrid Arena pavilion in December in Madrid, Spain. / Getty Images for Lexus

Updated January 5, 2022 at 5:47 PM ET

In normal times, Novak Djokovic would be warmly welcomed to the Australian Open, as the world No. 1 and the tournament's defending champion. But now, the reigning Australian Open men's champion — who is famously skeptical about the COVID vaccine and received a medical exemption from being vaccinated — is being barred entry to the country.

"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.

The agency said Djokovic "failed to provide appropriate evidence to meet the entry requirements to Australia, and his visa has been subsequently cancelled."

Prime Minister Scott Morrison tweeted: "Rules are rules, especially when it comes to our borders. No one is above these rules."

Djokovic spent the night at the Melbourne Airport as Australian government officials refused to let him enter the country for the Australian Open after an apparent visa mix-up, according to The Associated Press.

Djokovic avoided the country's strict vaccine requirements by getting an exemption, prompting many Australians, including the prime minister, to say the tennis star shouldn't get special treatment.

"Any individual seeking to enter Australia must comply with our border requirements," Morrison said on Wednesday after reporters asked him about the case.

"If he's not vaccinated, he must provide acceptable proof that he cannot be vaccinated for medical reasons," Morrison said of the Serbian, adding that the federal government is waiting to see what evidence Djokovic will provide to support his request.

"If that evidence is insufficient, then he won't be treated any different to anyone else and he'll be on the next plane home," Morrison said, hiking his thumb in the air for emphasis. "There should be no special rules for Novak Djokovic at all. None whatsoever."

Serbian President Aleksandar Vučić released a statement on Instagram about Djokovic's visa being terminated.

"I just finished a phone conversation with Novak Djokovic. I told our Novak that the whole of Serbia is with him and that our authorities are taking all measures to stop the harassment of the best tennis player in the world in the shortest possible period," Vučić said in his post.

"In accordance with all norms of international public law, Serbia will fight for Novak Djokovic, for justice and truth. By the way, Novak is strong, as we all know him," the president added.

During the pandemic, Djokovic has aired his skepticism about the COVID-19 vaccine, but he has also refused to confirm his vaccination status publicly. In recent months, Australia's vaccine requirements prompted Djokovic's father to say his son would likely not play there.

On Tuesday, Djokovic announced that he had been granted an exemption to compete in Melbourne after all. Tournament and state health officials confirmed the development.

Many Australians are furious that an elite athlete whose fitness is legendary and who holds or shares many of the top records in tennis is seemingly flouting their rules by claiming a special medical condition. The federal government says more than 91.6% of Australians age 16 and older are fully vaccinated.

"We have been taken for fools," said Kevin Bartlett, the Australian rules football legend and broadcaster.

Others said that giving a special exemption to Djokovic sends a message that undercuts vaccination drives and shows a lack of respect — for anyone who is vulnerable and for those fighting the global pandemic, as Australia's ABC reports.

When Djokovic arrives in Australia, any exemption he's granted by medical professionals "will have to stack up," Morrison said.

The prime minister added that while the amount of scrutiny on Djokovic is unusual, he isn't alone in seeking a vaccine exemption. In the past two years, he said, many other people have shown proof that they qualify for the accommodation.

"So the circumstance is not unique," Morrison said. "The issue is whether he has sufficient evidence to support that he would qualify for that exemption."

This story originally appeared on the Morning Edition live blog.

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