NEW YORK, NY - SEPTEMBER 09:  Stan Wawrinka (R) of Switzerland shakes hands with Kei Nishikori (L) of Japan after their Men's Singles Semifinal Match on Day Twelve of the 2016 US Open at the USTA Billie Jean King National Tennis Center on September 9, 2016 in the Flushing neighborhood of the Queens borough of New York City.  (Photo by Mike Hewitt/Getty Images)