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.

“The moment we arrived in Belgrade we went to be tested. My result is positive, just as Jelena’s, while the results of our children are negative,” Djokovic said in a statement.

Djokovic has been criticized for organizing the tournament and bringing in players from other countries amid the coronavirus pandemic.