Novak Djokovic of Serbia (1) celebrates after winning against Roger Federer of Switzerland (3) during their Men's Semi Final 2011 US Open match at the USTA Billie Jean King National Tennis Center in New York September 10, 2011. Djokovic won 6-7 (7/9), 4-6, 6-3, 6-2, 7-5.       AFP PHOTO / TIMOTHY A. CLARY (Photo credit should read TIMOTHY A. CLARY/AFP via Getty Images)