The world number one tennis star is the fourth player to contract the virus after taking part in the Adria Tour, which was hosted in Belgrade, Zadar and Croatia over the weekend.
Djokovic had been highly criticised for going ahead with the tournament and flouting social distancing guidelines.
In a statement on Instagram, Djokovic apologised for his wrongdoing.
“I am so deeply sorry our tournament has caused harm. Everything the organisers and I did the past month, we did with a pure heart and sincere intentions,” he shared.
“We believed the tournament met all health protocols and the health of our region seemed in good condition to finally unite people for philanthropic reasons.
“We were wrong and it was too soon. I can’t express how sorry I am for this and every case of infection.”
Fellow tennis players Borna Coric, Grigor Dimitrov and Viktor Troicki and Djocokiv’s wife Jelena all also tested positive for the coronavirus.
According to reports, social distancing measures were not observed at the matches and fans and players were seen hugging and mingling throughout the tournament.
Social media footage also showed Djokovic partying at a packed nightclub in Belgrade during the tournament.
“We organised the tournament at the moment when the virus has weakened, believing that the conditions for hosting the Tour had been met,” said Djokovic.
“Unfortunately, this virus is still present, and it is a new reality that we are still learning to cope and live with.”
Djokovic first faced controversy when he said he was against getting a COVID-19 vaccine should one be developed, even if it was required for travel.
Fellow Wimbledon champion Andy Murray criticised Djokovic for going ahead with the tournament amid the pandemic.
“When you are going through a time like this it’s important any of the top athletes around the world should be showing that we are taking this extremely seriously and knowing that we are using social distancing measures,” said Murray.
Djokovic, who is not showing any symptoms, says he will be self-isolating for 14 days and be tested again in five days.
