Serena Williams reacts after winning her semifinal match against Caroline Wozniacki of Denmark at the U.S. Open in New York on Saturday, Sept. 10, 2011. (AP Photo/Charlie Riedel)

Photo by: Charlie Riedel

Serena Williams reacts after winning her semifinal match against Caroline Wozniacki of Denmark at the U.S. Open in New York on Saturday, Sept. 10, 2011. (AP Photo/Charlie Riedel)