NEW YORK, NY - SEPTEMBER 05:  Tennis player Donna Vekic of Croatia watches Stan Wawrinka of Switzerland play Ruben Bemelmans of Belgium during their Men's Singles Third Round match on Day Six of the 2015 US Open at the USTA Billie Jean King National Tennis Center on September 5, 2015 in the Flushing neighborhood of the Queens borough of New York City.  (Photo by Clive Brunskill/Getty Images)