Novak Djokovic tested positive for the coronavirus on Tuesday after taking part in a tennis exhibition series he organized in Serbia and Croatia.
The top-ranked Serb is the fourth player to test positive for the virus after first playing in Belgrade and then again last weekend in Zadar, Croatia.
His wife also tested positive. Djokovic has been criticized for organizing the tournament and bringing in players from other countries amid the coronavirus pandemic.
There were no social distancing measures observed at the matches in either country.
Viktor Troicki said Tuesday he and his pregnant wife have both been diagnosed with the virus, while Grigor Dimitrov, a three-time Grand Slam semifinalist from Bulgaria, said Sunday he tested positive.
Borna Coric played Dimitrov on Saturday in Zadar and said Monday he has also tested positive.
Djokovic apologized to anyone who became infected as a result of the series and said he will be in self-isolation for 14 days.