Barclays ATP World Tour Finals - Day Three [Getty Images]

LONDON, ENGLAND - NOVEMBER 11: Roger Federer of Switzerland acknowledges the crowd after victory in the round robin singles match against Kei Nishikori of Japan on day three of the Barclays ATP World Tour Finals at the O2 Arena on November 11, 2014 in London, England. (Photo by Julian Finney/Getty Images)

Getty Images Sport Julian Finney