The outspoken opponent of vaccination campaigns was pictured welcoming players to his Adria Tour competition at the airport, hugging them during an accompanying football match, dancing at a piano in front of thousands of fans who had filled the seats at his tennis club and embracing his rivals in press photos while much of the world continues to observe social distancing.

Few members of the huge audience wore masks as they sat next to each other on the banks of the River Danube to watch top players including Alexander Zverev, Dominic Thiem, Grigor Dimitrov and Jelena Jankovic compete in the high-spirited exhibition event.

The surprising scenes were at odds with advice from the vast majority of global health experts on curbing the spread of COVID-19, sparking a row on social media between commentators concerned at Djokovic’s lack of caution and apologists who observed that Serbia’s death rates from the virus are currently low.

Just days earlier, 25,000 fans had been allowed to attend a fiery derby match between leading football teams Partizan and Red Star Belgrade where crowd restrictions were also not encouraged.

“Yes, this is footage from today and not from another planet,” said Stuart Fraser, the tennis correspondent for The Times, observing the action in front of 4,000 ticket buyers. 

“Oh to be a fly on the wall at the United States Tennis Association offices now.”

The US Open looks increasingly unlikely to take place as scheduled in late August against a backdrop of the widespread outbreak of the virus and social unrest across the country, with high-profile figures including Australian ace Nick Kyrgios calling tennis bosses “selfish” for pressing ahead with plans to host a restricted tournament earlier this week.

One fan reacted to photos of Djokovic asking fans to observe a minute’s silence in honor of the hundreds of thousands of people who have died from the virus worldwide as “no laughing matter.”

“I know piling on Novak seems like a sport at this point, but yikes,” they added.

“The tone-deafness and lack of awareness of it all, not to mention the irony. It’s like a portrait in satire except it’s all real.”

Djokovic defended his seemingly carefree attitude by claiming that the lack of a lockdown in his homeland meant there was no need for precautionary interventions.

“Of course, lives have been lost and that's horrible to see in the region and worldwide,” he acknowledged.

“But life goes on and we as athletes are looking forward to competing.

"We have different measures in Serbia than the United States or UK. It's not up to me to make the call on what is right or wrong health-wise. We are following what the government of Serbia is telling us.