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