US Open Tennis - Day 11 (20 images)

Serbia's Novak Djokovic celebrates after defeating Andy Roddick, U.S.A, eighth seed, during their quarter-final match at the U.S. Open tennis championship at the U.S. National Tennis Center on September 4, 2008 in Flushing Meadows, New York. Djokoic won 6-2, 6-3, 3-6, 7-6(5). (UPI Photo/Monika Graff)

Andy Roddick, U.S.A, eighth seed, returns the ball to Serbia's Novak Djokovic, third seed, in the second set at the U.S. Open tennis championship at the U.S. National Tennis Center on September 4, 2008 in Flushing Meadows, New York. (UPI Photo/Monika Graff)

Todd Martin, U.S.A, returns the ball to Michael Chang, U.S.A, in the exhibition singles match at the U.S. Open tennis championship at the U.S. National Tennis Center on September 4, 2008 in Flushing Meadows, New York. (UPI Photo/Monika Graff)

Gilles Muller of Luxumburg returns the ball to Roger Federer of Switzerland, second seed, in the third set of their quarterfinal match at the U.S. Open tennis championship at the U.S. National Tennis Center on September 4, 2008 in Flushing Meadows, New York. Federer won 7-6, 6-4, 7-6. (UPI Photo/Monika Graff)