Novak Djokovic of Serbia returns the ball to Grigor Dimitrov of Bulgaria during their round 3 match at the BNP Paribas 2016 Masters tennis tournament in Paris, France, 03 November 2016. EPA/IAN LANGSDON

Grigor Dimitrov of Bulgaria returns the ball to Novak Djokovic of Serbia during their round 3 match at the BNP Paribas 2016 Masters tennis tournament in Paris, France, 03 November 2016. EPA/IAN LANGSDON

Richard Gasquet of France arrives for his third round match against Jack Sock of the USA at the BNP Paribas 2016 Masters tennis tournament in Paris, France, 03 November 2016. EPA/IAN LANGSDON

John Isner of the US returns the ball to Jan-Lennard Struff of Germany during their round 3 match at the BNP Paribas 2016 Masters tennis tournament in Paris, France, 03 November 2016. EPA/IAN LANGSDON

Jan-Lennard Struff of Germany returns the ball to John Isner of the US during their round 3 match at the BNP Paribas 2016 Masters tennis tournament in Paris, France, 03 November 2016. EPA/IAN LANGSDON