ROME, ITALY - MAY 15: Novak Djokovic of Serbia in action during his Third Round match against Kei Nishikori of Japan on Day Six of the The Internazionali BNL d'Italia 2015 at Foro Italico on May 15, 2015 in Rome, Italy. (Photo by Ian Walton/Getty Images)
LONDON, ENGLAND - JULY 02: Dustin Brown of Germany reacts in his Gentlemens Singles Second Round match against Rafael Nadal of Spain during day four of the Wimbledon Lawn Tennis Championships at the All England Lawn Tennis and Croquet Club on July 2, 2015 in London, England. (Photo by Ian Walton/Getty Images)
LONDON, ENGLAND - JULY 01: Stanislas Wawrinka of Switzerland serves in his Gentlemens Singles Second Round match against Victor Estrella Burgos of Dominican Republic during day three of the Wimbledon Lawn Tennis Championships at the All England Lawn Tennis and Croquet Club on July 1, 2015 in London, England. (Photo by Ian Walton/Getty Images)
