NEW YORK, NY - SEPTEMBER 08:  Marin Cilic of Croatia reacts after defeating Kei Nishikori of Japan to win the men's singles final match on Day Fifteen of the 2014 US Open at the USTA Billie Jean King National Tennis Center on September 8, 2014 in the Flushing neighborhood of the Queens borough of New York City.  (Photo by Mike Stobe/Getty Images for USTA)