NEW YORK, NY - SEPTEMBER 08:  Kei Nishikori of Japan looks on against Marin Cilic of Croatia prior to their 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 Alex Goodlett/Getty Images)