Just when it seemed Novak Djokovic could put his experience at the 2022 Australian Open behind him, the Serb has been hit by a new scandal in regards to the timing of his Covid-19 test results.
Unvaccinated Djokovic, 34, travelled to Melbourne in early January under the impression that a positive Covid-19 test dated December 16 would count as a medical exemption to compete.
Despite having that cleared with Tennis Australia and the Victorian government, border officials turned the world No 1 away as it did not meet the Australian federal government's criteria.
However, data uncovered by the BBC calls into question the accuracy of the samples provided by Djokovic and his team as he attempted to win a record-extending 10th Australian Open title.
German website Der Spiegel first raised suspicion with the documents submitted to Australia's federal court by Djokovic's lawyers on January 10.
Those documents included two coronavirus (PCR) test certificates, one pertaining to the positive result on December 16, and a second relating to his negative result six days later on December 22.
Djokovic received his results from the Institute of Public Health of Serbia, and it was confirmed by acting director of Serbia's official health body that the dates cited reflected when those tests were undertaken.
However, the call for further inspection came after it was noticed the serial number on his first, positive test (7371999) was greater than that of his second, negative test (7320919) less than one week later.
The BBC compared these results alongside more than 50 other serial numbers—all issued by Serbia's Institute of Public Health—obtained from BBC staff and Milovan Suvakov, a Serb research scientist in the United States.
The samples used corroborated the trend that the earlier a test was undertaken, the lower the number should be, placing Djokovic's positive test as the only one seemingly out of sync with its peers.
By that logic, the 20-time Grand Slam winner's positive test—allegedly submitted on December 16—fits between those results corresponding to the dates of December 25 (7366969) and December 28 (7415312).
"There is always the possibility for a glitch," Djordje Krivokapic—a data and digital security specialist—told BBC News.
"But if that were the case, there would be a simple explanation," he says. "I don't see why the state authorities wouldn't just say that."
Although Djokovic's two samples were processed at two different laboratories, there's nothing to suggest different sites produce a different set of codes.
In fact, the BBC's research samples were processed at eight separate labs, with no evidence to suggest this should lead to a difference in the confirmation code.
“The test results also include QR codes. And when Der Spiegel scanned the QR code for the test from December 16, things got strange. On Monday, the result from the scan was ‘test result negative’," DerSpiegel wrote in its report. It's alleged this sample later resulted in a positive.
The top men's player in the world has signed on to play the Dubai Tennis Championships in February, where no such vaccine requirements are in place.
Djokovic may find himself playing catch-up in the major medal race, however, after Rafael Nadal advanced to set up an Australian Open decider against Daniil Medvedev.
The Spaniard could pull clear of 'Nole' and Roger Federer by becoming the first men's player to reach 21 Grand Slam singles titles, in which case Djokovic would face a longer wait to potentially break the record himself.
