Sep 1, 2016; New York, NY, USA; Stan Wawrinka of Switzerland hits a forehand against Alessandro Giannessi of Italy (not pictured) on day four of the 2016 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Wawrinka won 6-1, 7-6(4), 7-5. Mandatory Credit: Geoff Burke-USA TODAY Sports