Serbian Novak Djokovic serves to France’s Jeremy Chardy during their men’s semi-final singles match at the Rogers Cup Open ATP tennis tournament in Montreal, Canada, 15 August 2015. EPA/ANDRE PICHETTE

France’s Jeremy Chardy returns a ball to Serbian Novak Djokovic during their men’s semi-final singles match at the Rogers Cup Open ATP tennis tournament in Montreal, Canada, 15 August 2015. EPA/ANDRE PICHETTE

Serbian Novak Djokovic returns a ball to France’s Jeremy Chardy during their men’s semi-final singles match at the Rogers Cup Open ATP tennis tournament in Montreal, Canada, 15 August 2015. EPA/ANDRE PICHETTE

France’s Jeremy Chardy serves to Serbian Novak Djokovic during their men’s semi-final singles match at the Rogers Cup Open ATP tennis tournament in Montreal, Canada, 15 August 2015. EPA/ANDRE PICHETTE

Kei Nishikori of Japan in action against Andy Murray of Great Britain during their men’s semi-final singles match at the Rogers Cup Open ATP tennis tournament in Montreal, Canada, 15 Aug 2015. EPA/ANDRE PICHETTE

A multiple exposure picture shows Andy Murray of Great Britain in action against Kei Nishikori of Japan during their men’s semi-final singles match at the Rogers Cup Open ATP tennis tournament in Montreal, Canada, 15 Aug 2015. EPA/ANDRE PICHETTE

Kei Nishikori of Japan looks over to Andy Murray of Great Britain during their men’s semi-final singles match at the Rogers Cup Open ATP tennis tournament in Montreal, Canada, 15 Aug 2015. Nishikori lost. EPA/ANDRE PICHETTE

Andy Murray of Great Britain in action agsint Kei Nishikori of Japan during their men’s semi-final singles match at the Rogers Cup Open ATP tennis tournament in Montreal, Canada, 15 Aug 2015. EPA/ANDRE PICHETTE