Dominic Thiem believes he and other tennis players who took part in Novak Djokovic's Adria Tour "acted too euphorically" and that their behaviour was "a mistake" given the reality of the Covid-19 pandemic.
Thiem further revealed that he had gotten himself tested five times in the last 10 days and that he had always tested negative.
"I was shocked when I got the news from the Adria Tour. We played without any audience for weeks, so we have been more than happy about the fans at the event," Thiem said in a statement posted to Instagram.
"We trusted the Serbian government's corona rules, but we have been too optimistic. Our behavior was a mistake, we acted too euphorically. I am extremely sorry.
"I've now got tested five times within the last ten days and the result was always negative. I wish everyone who is infected all the best and a quick recovery."
Djokovic, Grigor Dimitrov, Borna Coric and Viktor Troicki all tested positive for coronavirus after playing in the first two legs of Djokovic's ill-fated Adria Tour in Belgrade and Croatia. Djokovic's wife Jelena also tested positive.
Around 4,000 spectators watched the Belgrade event where there was no social distancing. Players were also photographed shirtless, dancing the night away at a packed Belgrade club.
However, Djokovic’s parents defended their son on Wednesday and blamed another tennis player for spreading the coronavirus.
“Why did it happen? Because that man probably came sick, who knows from where,” Srdjan Djokovic told RTL Croatia TV. “He didn’t test here, he tested somewhere else ... I think that’s not fair."
Images and videos of the players hugging at the net, playing basketball together and partying at the event have also been posted on social media.
(With inputs from Agencies)