Later on that day Serena Williams held off a stiff challenge from Varvara Lepchenko, doing well to win in straight sets 6-3 603 in very difficult, windy conditions.
Then on Sunday, the reigning French Open champion Maria Sharapova was ousted in three very entertaining sets 6-4 2-6 6-2 by a very determined Caroline Wozniacki. Wozniacki will next play Sara Errani and the former World #1 has a very good chance to reach her 3rd U.S. Open final in five years thanks to the upsets which have plagued the bottom half of the draw.
The first big upset occurred on the Men's Side on Sunday with #4 seed David Ferrer losing to Gilles Simon. This could potentially be bad news for Roger Federer, who has never lost to Ferrer but has often struggled against the Frenchman Simon, if both players reach the semifinals by winning their next two matches.