Melbourne - Alexander Zverev believes there are probably more players with Covid at the Australian Open after 29th seed Ugo Humbert said Wednesday that he tested positive following his first-round loss.
The 23-year-old Humbert was beaten by fellow Frenchman Richard Gasquet on Tuesday and subsequently wrote on Instagram: "I was tested positive on my exit test yesterday and I'll stay one more week in isolation in Australia.
"Thanks for your support and see you soon."
All players at the Australian Open must be vaccinated or have a medical exemption - the rule was central to the saga surrounding unvaccinated number one Novak Djokovic, who was deported on the eve of the tournament after the government cancelled his visa.
Infection rates have surged in Australia since December and Tokyo Olympic champion Zverev, who was a comfortable second-round winner over Australia's John Millman, said afterwards he was limiting how much he goes out in public to avoid exposure to the virus.
The German said it was inevitable there would be more cases among players.
"Look, I think this year in Australia is a lot more cases than last year, simple as that," he said.
"And we are allowed to go outside to eat, allowed to do whatever we want, so I think it's natural that more people get Covid," added Zverev, who believes "quite a few players" are already infected.
"We are not getting tested so I think if we would get tested there would be probably more positives than there are now, in a way."