In April 2020, with the pro tennis tour suspended because of the coronavirus pandemic, Novak Djokovic took part in a Facebook Live chat with some fellow Serbian athletes. During their conversation, Djokovic, famous for his punishing training regimen, abstemious diet and fondness for New Age beliefs, said he was “opposed to vaccination” and “wouldn’t want to be forced by someone to take a vaccine in order to be able to travel.”

“But if it becomes compulsory, what will happen? I will have to make a decision,” he said.

More than a year and a half later, Djokovic’s decision to seek a medical exemption to the Australian Open’s vaccine requirement has become a debacle for tennis — and one of the most bizarre episodes yet served up by the pandemic. Djokovic, 34, has done potentially irreparable harm to his own image. It is a bitter twist for a player who has long craved the adoration lavished on his chief rivals, Roger Federer and Rafael Nadal, and it is a sad coda to what is widely considered the greatest era in the history of men’s tennis.

Djokovic arrived in Australia aiming to notch a record 21st Grand Slam singles title, which would put him one ahead of Federer and Nadal and strengthen his claim to being the most accomplished men’s player of all time. Instead, he now finds himself at the center of a global controversy that turns on some of the most divisive issues raised by the pandemic, in particular the question of individual freedom versus collective responsibility.

Djokovic’s refusal to capitulate to an Australian government that has sought to bar him “in the public interest” because he is unvaccinated has made him a martyr in the eyes of some right-wing populists and those who oppose vaccines, and has elicited an outpouring of rage in Serbia.

While Djokovic was sequestered in a Melbourne hotel room awaiting a court hearing on his entering the country, Nigel Farage, the far-right British politician and media figure who spearheaded the Brexit campaign, was in Belgrade, Serbia, expressing solidarity with the tennis star’s family. Djokovic’s father compared his son to Jesus Christ and Spartacus and hailed him as “the leader of the free world.” In Melbourne, a raucous crowd of Djokovic supporters chanted “Novak” and clashed with the police.

All of this is a strange turn of events for an athlete who has often been accused of trying too hard to win the world’s affection and who commands enormous respect within his sport, and not just because he has done so much winning. He’s a popular figure in the locker room, where he is seen as a strong advocate for players who are struggling financially: In 2020, he co-founded a players’ association with the stated goal of making tennis more remunerative for those down the ranks, though it’s unclear what that group has accomplished since. Djokovic also has distinguished himself with his philanthropy and with the graciousness he has shown Federer and Nadal. (“He’s a magnificent champion,” Djokovic said of Federer after beating him at Wimbledon in 2014.)

In person, he is affable and engaging, with a keen interest in life beyond the baseline and a palpable sense of gratitude for his good fortune. Djokovic grew up during the Balkan wars of the 1990s — he was in Belgrade when NATO forces bombed Serbia and spent many nights huddled in the basement of his grandfather’s apartment building.

Djokovic has said that the experience helped harden him into the champion he became. But it perhaps also bred a sense of imperviousness that has now led him astray.

This standoff in Australia has also put a spotlight on some of the more troubling aspects of Djokovic’s public persona. He has long been a spiritual dabbler, with a weakness for what some regard as quackery. A few years ago, when Djokovic was mired in a slump, there was concern he had fallen under the sway of a Spanish tennis coach named Pepe Imaz, whose training philosophy, called Amor y Paz, or Love and Peace, emphasized meditation and group hugs. (“Human beings have infinite capacities and skills, the problem is that our mind limits us,” Imaz said on his website. “Telepathy, telekinesis, and many more things are all possible.”) In a video on YouTube, Djokovic is shown onstage with Imaz talking about the “need to be able to look inwards and to establish this connection with a divine light.”

When the tennis tour was on hiatus during the spring of 2020, Djokovic did several Instagram chats with the wellness guru Chervin Jafarieh. During one of their conversations, Djokovic claimed that the mind could purify water.

“I know some people that, through energetical transformation, through the power of prayer, through the power of gratitude, they managed to turn the most toxic food, or maybe the most polluted water, into the most healing water, because the water reacts,” he said. “Scientists have proven that in experiment, that molecules in the water react to our emotions to what has been said.” (“The people of Flint, Michigan, would love to hear that news,” the tennis commentator Mary Carillo replied.)

It was during this same period that Djokovic revealed on Facebook Live his opposition to vaccines and vaccine mandates. A few months later, he hosted an exhibition tour in the Balkans that became a superspreader event. Djokovic and his wife were among those who tested positive for the coronavirus. In the press and in tennis circles, Djokovic was pilloried for staging matches — with fans in attendance — during a public health crisis. But it was nothing compared to the opprobrium he has faced this month, particularly in Australia, where the public is chafing under Covid restrictions, and the Djokovic fight is playing out against the backdrop of an upcoming national election.

Back in Serbia, however, Djokovic is seen as a victim who is being victimized because he is Serbian. “They are stomping all over Novak to stomp all over Serbia and Serbian people,” Djokovic’s father, Srdjan, told reporters. The Serbian foreign ministry put out a statement saying that the Serbian public “has a strong impression” that Djokovic was “lured to travel to Australia in order to be humiliated” and that it was feeling “understandable indignation.”

The Djokovic flap has come at a time of resurgent Serbian nationalism in Bosnia, and it has also revived interest in Djokovic’s political views. On a visit to Bosnia last September, he was photographed with the former commander of a paramilitary group that was implicated in the 1995 Srebrenica massacre. He was also videotaped singing at a wedding with Milorad Dodik, the hard-line Serbian nationalist whose separatist rhetoric is raising fears that Bosnia might again fall into conflict.

Djokovic has made comments over the years that suggested he was at least sympathetic to Serbian nationalism. In a speech in 2008, he said that Kosovo belonged to Serbia after it declared independence. On the other hand, he’s coached by a Croat, the former Wimbledon champion Goran Ivanisevic, and is seen by many in the Balkans as a conciliatory figure. People around Djokovic believe that he is not as popular as Federer and Nadal in part because he comes from a small country with a bad reputation. But that’s not necessarily an expression of Serbian nationalism, and there’s likely some truth to it.

The Bosnian-American writer Aleksandar Hemon, who teaches at Princeton (and is a co-writer of “The Matrix Resurrections” screenplay), suggested that what Djokovic actually thinks is almost beside the point: His world-conquering success has made him a mythological figure in Serbian culture, the embodiment of Serbian greatness who has landed a crushing blow against the enemies of his country.

“He has great value,” Hemon said. “He’s kind of evidence that we are better than they think we are.”

And likewise, the Djokovic controversy in Australia has played into the sense of victimhood that animates Serbian nationalism — a belief that “the West hates him because he’s a Serb,” as Hemon put it.

The indignation in Serbia may not subside even after the Australian Open ends. If Djokovic continues to resist vaccination, his ability to travel and to play other tournaments could be limited. For the duration of the pandemic, the best tennis player in the world may be an international pariah. Paul Annacone, who coached Federer and is now a commentator for the Tennis Channel, said the Djokovic situation saddens him.

“It’s a damn shame,” he said, “and I feel especially bad for tennis.”

This is the second time in a matter of months that tennis has found itself at the center of an international dispute. The disappearance in November of the Chinese player Peng Shuai, after she publicly accused a former senior government official of sexual assault, renewed concern about China’s human rights record and has cast a shadow over the Beijing Winter Olympics, which begin in three weeks. In the case of Peng, the tennis community came together to demand proof of her safety and well-being, and the response has become a source of pride for the sport.

Not so for the Djokovic affair, which is purely an embarrassment. While it appears that bureaucratic bungling is at least partly to blame, Djokovic has been the architect of his own troubles. He submitted a visa application that included incorrect and possibly misleading information, and had the temerity to show up unvaccinated in a country that has endured some of the world’s strictest Covid-19 lockdowns and that is sagging under the Omicron variant. At the very least, Djokovic’s approach suggested insensitivity, although his critics, whose numbers are growing by the hour, are more inclined to see it as callous indifference. His recent admission that he had gone ahead with an interview with a French journalist in December after supposedly contracting the coronavirus has caused especially intense outrage. (The reporter said that Djokovic did not disclose that he had tested positive.)

Whether it was miscalculation, arrogance or some combination of the two that led Djokovic to think he could show up in Melbourne unvaccinated and just play, he now finds himself isolated in the tennis world. Few players have publicly supported him. The former world No. 1 Martina Navratilova said that she had always spoken up for Djokovic and felt that he got “a raw deal” from fans who were hostile to him. But not now.

“I’ve been defending Novak for many years,” she said, “but I cannot defend him on this one.”