Those emotions have been magnified by the decision to grant the world No.1 a medical exemption to compete in the Australian Open.

Figures within tennis, however, have initially either been quiet, or coy at the news, though this is partly explained by it breaking late in the Australian evening when many of the players preparing in Australia for the grand slam were either heading for bed or away from media outlets.

Jamie Murray, the British doubles player, was neither having just competed in the ATP Cup. When asked his thoughts he said: "I think if it was me that wasn't vaccinated I wouldn't be getting an exemption." After a pause he added: "But well done to him for getting clear to come to Australia and compete."

The reaction of the players alongside Murray at the press conference suggested this was a minefield few were prepared to cross. Certainly the Australian players James Duckworth and Alex de Minaur were more circumspect, if not exactly overjoyed at the news.

"I don't know the criteria for exemptions ,apparently it's an independent panel, he must have fit the criteria somehow, so, yeah, if he's fit the criteria, then, yeah, he should be able to come," said Duckworth.

De Minaur responded with a laugh: "That's very politically correct of you."

The Australian No.1 added: "I just think it's just very interesting, that's all I'm going to say. But, hey, it is what it is, I just hope that the other players that I heard there were other cases as well, they got exemptions, so I hope they will all fit the criteria."

Richard Ings, the former head of Australia's anti-doping authority ASADA, and a keen advocate of vaccination, was less reticent.

"Clearly all this talk about vaccination status being personal and private only held water up to the point of tossing it back in the face of vaccinated Australians," he wrote on twitter.

Ings was replying to the post in which Djokovic announced he was heading for Melbourne, accompanied by a photo of him with packed bags at an airport.

Seven hours after sending this the Serbian had received 32,400 likes, 6,500 retweets and 5,900 replies.

Given he has 8.8m followers those numbers are not particularly large. More pertinent was the content. There was a significant hard-core of support, much of it from compatriots or anti-vaxxers.

But there was far more criticism, often very strongly worded, a lot of it from Australians, many of whom also took aim at their own Government .

The response was similar in old media. Under the sub-headline 'Fury at No-vax grand slam shock' the splash headline in the Brisbane Courier-Mail was 'You must be Djoking'.

Australian Associated Press