Borna Coric announced on Monday he has become the second player to test positive for coronavirus after taking part in an exhibition tournament in Croatia featuring world number one Novak Djokovic.
"Hi everyone, I wanted to inform you all that I tested positive for COVID-19," the Croatian, ranked 33rd in the world, posted on Twitter.
It follows Sunday's announcement by Grigor Dimitrov that he had also tested positive after pulling out of the exhibition event, which is one of the biggest since the tennis season was halted because of the pandemic.
READ MORE
Former Bangladesh captain Mashrafe tests positive for virus
Iraqi football legend Radhi dies from COVID-19
Coric tweeted: "I want to make sure anyone who has been in contact with me during the last few days gets tested!
"I am really sorry for any harm I might have caused! I'm feeling well and don't have any simptoms (sic). Please stay safe and healthy! Lots of love to all!"
Borna Coric reacts during the match against Diego Schwartzman at the ATP Cup tournament in Sydney. File/AFP
One of Djokovic's coaches and another member of Dimitrov's entourage have also reportedly tested positive for the virus, according to Croatia's N1 television channel.
Coric had beaten Bulgaria's Dimitrov in the second leg of the Adria Tour in Zadar on Croatia's Adriatic coast on Saturday.
Dimitrov withdrew from the Balkans tournament following that match, complaining of feeling unwell.
Sunday's final between Djokovic and Russia's Andrey Rublev was immediately cancelled as a precaution.
Australian star Nick Kyrgios responded to Coric's tweet by describing the staging of the tournament as "boneheaded".
Agence France-Presse