Novak Djokovic of Serbia celebrates after defeating Stanislas Wawrinka of Switzerland in five sets during their semifinals match at the U.S. Open Championship held at the USTA Billie Jean King National Tennis Center on September 7, 2013 in New York City. Djokovic won 2-6,7-6, 3-6, 6-3, 6-4. UPI /Monika Graff