Alexandr Dolgopolov Pictures
LONDON, ENGLAND - JULY 04: Alexandr Dolgopolov of Ukraine walks off court as he retires injured after the Gentlemen's Singles first round match against Roger Federer of Switzerland on day two of the Wimbledon Lawn Tennis Championships at the All England Lawn Tennis and Croquet Club on July 4, 2017 in London, England. (Photo by Michael Steele/Getty Images)