Sloane Stephens of the USA in action against Lucie Safarova of the Czech Republic during their third round match for the Wimbledon Championships at the All England Lawn Tennis Club, in London, Britain, 03 July 2015. EPA/GERRY PENNY

John Isner of the USA in action against Marin Cilic of Croatia during their third round match for the Wimbledon Championships at the All England Lawn Tennis Club, in London, Britain, 03 July 2015. EPA/FACUNDO ARRIZABALAGA

Grigor Dimitrov of Bulgaria plays Richard Gasquet of France in their third round match during the Wimbledon Championships at the All England Lawn Tennis Club, in London, Britain, 03 July 2015. EPA/SEAN DEMPSEY

Novak Djokovic of Serbia returns to Bernard Tomic of Australia in their third round match during the Wimbledon Championships at the All England Lawn Tennis Club, in London, Britain, 03 July 2015. EPA/SEAN DEMPSEY

Maria Sharapova of Russia in action against Irina-Camelia Begu of Romania during their third round match for the Wimbledon Championships at the All England Lawn Tennis Club, in London, Britain, 03 July 2015. EPA/FACUNDO ARRIZABALAGA