2013 U.S. Open - Day 13

In This Photo: Stanislas Wawrinka
Stanislas Wawrinka of Switzerland changes his racquet during his men's singles semifinal match against Novak Djokovic of Serbia on Day Thirteen of the 2013 US Open at USTA Billie Jean King National Tennis Center on September 7, 2013 in the Flushing neighborhood of the Queens borough of New York City.
(Sept. 6, 2013 - Source: Maddie Meyer/Getty Images North America)