LONDON, ENGLAND - JULY 04:  Grigor Dimitrov of Bulgaria slips over as he tries to make a return during the Gentlemen's Singles semi-final match against Novak Djokovic of Serbia on day eleven of the Wimbledon Lawn Tennis Championships at the All England Lawn Tennis and Croquet Club on July 4, 2014 in London, England.  (Photo by Al Bello/Getty Images)