U.S. Open 2011 (153 images)

Roger Federer of Switzerland, third seed, returns the ball to Juan Monaco of Argentina in fourth round action at the U.S. Open held at the National Tennis Center on September 6, 2011 in New York. UPI/Monika Graff

Svetlana Kuznetsova (L) of Russia, fifteenth seed, and Caroline Wozniacki of Denmark, first seed, shake hands at the conclusion of their match where Wozniacki won in fourth round action at the U.S. Open held at the National Tennis Center on September 5, 2011 in New York. Wozniacki won 6-7, 7-5, 6-1. UPI/Monika Graff

Francesca Schiavone of Italy, seventh seed, returns the ball to Chanelle Scheepers of South Africa in third-round action at the U.S. Open held at the National Tennis Center on September 3, 2011 in New York. UPI/Monika Graff

Caroline Wozniacki of Denmark, first seed, returns the ball to Vania King, USA, in third-round action at the U.S. Open held at the National Tennis Center on September 3, 2011 in New York. Wozniacki won 6-2,6-4. UPI/Monika Graff