Dominic Thiem admits the ill-fated Adria Tour was a 'mistake'

Four players, including world No 1 and organiser Djokovic, have tested positive for coronavirus after participating in the series

Novak Djokovic in action against Viktor Troicki during their match for the Adria Tour tennis tournament in Belgrade, Serbia. EPA

Bulgaria's Grigor Dimitov and Germany's Alexander Zverev at the trophy ceremony during the Adria Tour at Novak Tennis Centre in Belgrade, Serbia. Reuters

Germany's Alexander Zverev in action during the Adria Tour. Reuters

Djordje Djokovic and Goran Ivanisevic during a press conference announcing the cancellation of the Adria Tour final. Reuters

Djordje Djokovic and Goran Ivanisevic announce the cancellation of the Adria Tour final after Grigor Dimitrov tested positive for the coronavirus. Reuters

Novak Djokovic hugs Jelena Jankovic during a tennis doubles against Serbia's Nenad Zimonjic and Olga Danilovic at a charity exhibition hosted by Novak Djokovic, in Belgrade. AFP

Serbia's Viktor Troicki, Nenad Zimonjic, Dusan Lajovic, Novak Djokovic, Austria's Dominic Thiem and Bulgaria's Grigor Dimitrov during Adria Tour at Novak Tennis Centre in Belgrade, Serbia, June 12. Reuters

Serbia's Novak Djokovic with his wife Jelena in the stands in Belgrade. Both have contracted Covid-19. Reuters

Novak Djokovic during Adria Tour at Novak Tennis Centre in Belgrade, Serbia, June 14. Reuters

Serbia's Novak Djokovic poses for a picture before the match with Serbia's Pedja Krstin. Reuters

Serbia's Novak Djokovic poses next to Biserka Petrovic during a press conference in Zadar, Croatia on June 19. Reuters

Serbia's Novak Djokovic poses for picture next to Croatia's Marin Cilic and Borna Coric. Reuters

Grigor Dimitrov, centre, with Alexander Zverev, left, and Novak Djokovic courtside at the Adria Tour. EPA

Grigor Dimitrov, centre, with Alexander Zverev, left, and Novak Djokovic at the Adria Tour. EPA

Grigor Dimitrov plays basketball with Novak Djokovic in Zadar, Croatia, during the Adria Tour. AP Photo

Spectators watch a match during the Adria Tour, an exhibition tournament, in Zadar, Croatia. AP Photo

Grigor Dimitrov, right, poses for photos with Borna Coric during their Adria Tour semifinal in Zadar, Croatia. AP Photo

From left, Dusan Lajovic, Viktor Troicki, Grigor Dimitrov, Filip Krajinovic, Dominic Thiem, Alexander Zverev and Novak Djokovic during the Adria Tour. AFP

Grigor Dimitrov, facing camera, shakes hands with Dominic Thiem at the end of their match at the Adria Tour. AFP

Grigor Dimitrov greets Dominic Thiem at the end of their match at the Adria Tour. AFP

Dominic Thiem serves to Grigor Dimitrov during the Adria Tour in Belgrade, Serbia. Getty Images

Dusan Lajovic serves to Grigor Dimitrov during a match at the Adria Tour in Belgrade. AFP

World No 3 Dominic Thiem has admitted that players who took part in the ill-fated Adria Tour made "a mistake" after Novak Djokovic and three other participants contracted coronavirus.

Thiem took part in the Belgrade leg of the exhibition event organised by Djokovic where social distancing was minimal and matches were played in front of thousands of fans.

The Serbian world No 1, Grigor Dimitrov, Borna Coric and Viktor Troicki all tested positive for Covid-19 after an event where players embraced across the net, played basketball, and host kids' clinics.

Djokovic also organised nights out in Belgrade for the players and videos of him dancing with the other participants were posted on social media.

Thiem, who left for an exhibition tournament in  France after Belgrade, says he has tested negative five times since leaving the Balkans.

"I was shocked when I got the news from the Adria Tour," he wrote on social media in his first public reaction since the tournament was cancelled on Sunday.

"We played without any audience for weeks, so we have been more than happy about the fans at the event. We trusted the Serbian government's coronavirus rules, but we have been too optimistic.

"Our behaviour was a mistake, we acted too euphorically. I am extremely sorry. I've been tested five times in the past 10 days and each time and the result was always negative."

Djokovic, 33, has come in for heavy criticism over the debacle, saying on Tuesday that he was "so deeply sorry" that the tournament "caused harm". His wife Jelena has also tested positive.

Australian player Nick Kyrgios described the call to go ahead with the tournament as "boneheaded", while former world No 1 Andy Murray said the event had not "been a great look for tennis".

The affair has raised concern over the planned restart of professional tennis in August, including the US Open which is scheduled to begin on August 31.