Novak Djokovic 

American great Andre Agassi has announced his separation with Novak Djokovic to end his 11-month coaching relationship with former world No. 1. Eight-time grand slam champion Agassi started his stint as Djokovic's coach in May last year. However, Djokovic has been witnessing a downfall in his career after claiming his 16th grand slam at the French Open in 2016. The Serb also failed to defend his title at Roland Garros last year, before retiring injured in the Wimbledon quarter-finals.