Serena Williams defeats Ana Ivanovic in quarterfinal action at the U.S. Open in New York

Serena Williams, USA, loses her footing as she takes on Ana Ivanovic, Serbia, in the first set of their quarterfinal match during the 2012 U.S. Open held at the National Tennis Center on September 5, 2012. Williams won 6-1, 6-3. UPI Photo/Monika Graff