US Open Tennis - Day 8 (29 images)

Serena Williams hits a backhand in her match against Severine Bremond on day eight at the U.S. Open Tennis Championships at the U.S. National Tennis Center in Flushing Meadows, New York on September 1, 2008. Williams defeated Bremond 6-2 6-2. (UPI Photo/John Angelillo)

Serena Williams reacts after a challenge in her match against Severine Bremond on day eight at the U.S. Open Tennis Championships at the U.S. National Tennis Center in Flushing Meadows, New York on September 1, 2008. Williams defeated Bremond 6-2 6-2. (UPI Photo/John Angelillo)

Andy Murray reacts after match point in his match against Stanislas Wawrinka on day eight at the U.S. Open Tennis Championships at the U.S. National Tennis Center in Flushing Meadows, New York on September 1, 2008. Murray defeated Wawrinka 6-1 6-3 6-3. (UPI Photo/John Angelillo)

Kei Nishikori runs to hit a forehand in his match against Juan Martin Del Potro on day eight at the U.S. Open Tennis Championships at the U.S. National Tennis Center in Flushing Meadows, New York on September 1, 2008. Del Potro defeated Nishikori 6-3 6-4 6-3. (UPI Photo/John Angelillo)