Caroline Wozniacki, of Denmark, returns to Svetlana Kuznetsova, of Russia, in the fourth round of the U.S. Open tennis tournament, Monday, Sept. 5, 2011, in New York. (AP Photo/Elise Amendola)

Photo by: Elise Amendola

Caroline Wozniacki, of Denmark, returns to Svetlana Kuznetsova, of Russia, in the fourth round of the U.S. Open tennis tournament, Monday, Sept. 5, 2011, in New York. (AP Photo/Elise Amendola)