As Novak Djokovic handed out the gongs at a youth tennis gala in Belgrade on Dec 17, Serbian sporting chiefs were scrambling to avoid more Covid embarrassment for their biggest star.

Another pandemic PR disaster – 18 months after he had to apologise over an alleged superspreading event – was always the biggest risk for the national hero ahead of the Australian Open.

To see off potential criticism at the time, Djokovic, the federation explained, would only meet “award-winning children, without a wider audience due to epidemiological measures”.

However, now it is his decision merely to leave home that day which is causing the greatest concern ahead of his fate being decided in Australia on Monday. Ahead of a hearing to finally decide whether he can be allowed entry to compete, his legal team told the Federal Circuit and Family Court on Saturday that the player tested positive on Dec 16.

There may be an innocent explanation for Djokovic pressing ahead with attending the Belgrade awards ceremony, posing mask-free alongside dozens of youngsters. The legal papers did not specify whether he had taken the test after experiencing symptoms or whether he had been notified of the result on the same day that it was recorded.

But public health experts say Djokovic should now feel “morally compelled” to set out the exact chain of events to reassure the public over his movements. “There is an obvious duty to clarify things as it doesn’t sound like responsible behaviour,” said Prof Gabriel Scally, president of the epidemiology and public health section of the Royal Society of Medicine. “We have to establish why he had the test, because, of course, he might have had Covid weeks previously. However, if he was symptomatic or if it was a screening test, then he should have been isolating.”

The latest twist in Djokovic’s pandemic saga draws a sharp contrast with the events of July 2020, when he was much more forthcoming about the details of his first positive test.

Sport’s most high profile anti-vaxxer had caught the virus then, along with his wife, Jelena, as the sport resumed from a four-month lockdown. Having joined three other leading players and two trainers infected by the disease towards the end of his unsanctioned Adria Tour, he appeared to recognise the error of his ways. He said Covid was “the new reality”, although he had organised his tour “with a philanthropic idea” and said he was sorry for the other people who tested positive.