In this photo taken on Sunday, June 14, 2020, Serbia's Novak Djokovic, centre, poses with volunteers and players after the Adria Tour charity tournament in Belgrade, Serbia. Djokovicâ€™s charity tennis exhibition series combined with an overall softening of coronavirus restrictions in Serbia has led to a spike in the number the positive cases among professional athletes. Two tennis players ranked among the top 40 in the world and five players at Serbiaâ€™s biggest soccer club have tested positive for the virus after being involved in sporting events where fans packed into the stands and social distancing was not enforced.