Kim Clijsters made a memorable comeback from retirement at the Flushing meadows when she won the tournament in 2009. She successfully defended it in 2010 and would have again been the favourite to win it had an injury not forced her to pull out. Her absence surely boosts the chances of a few other women who look likely to lay their hands on the trophy.
A look at the leading contenders for the US Open women's title, the final Grand Slam tournament of the season:
World ranking: 29 Career Singles titles: 39; Grand Slam singles titles: 13 Best US Open result: Winner (1999, 2002, 2008)
After 11 months out of action with a serious foot injury and a life-threatening blood clot, Williams returned in June. Her bid to defend her Wimbledon title ended with an early exit, but she has since lifted the trophies at Stanford and Montreal to put her firmly among the favourites at Flushing Meadows. A mid-week withdrawal from Cincinnati with a sore toe appeared to be a precaution, rather than a serious concern that injury would keep her out of the last Grand Slam of the season. Still rebuilding her world ranking, Williams used a special protected ranking afforded to players with prolonged injury layoffs to enter the main draw of the US Open.
World ranking: 4 Career Singles titles: 24; Grand Slam singles titles: 3 Best US Open result: Winner (2006)
Has clawed her way back up the world rankings after reaching the French Open semi-finals, where she suffered a frustrating defeat against eventual champion Li Na. Went one better at Wimbledon, reaching the final but fell to Czech Petra Kvitova. Believes that her big-hitting shots allied to the fact that she is finally injury-free could allow her to go deep into the tournament she won five years ago. Tuned up with a triumph at Cincinnati.
World ranking: 1 Career Singles titles: 17; Grand Slam singles titles: 0 Best US Open result: Runner-up (2009)
Wozniacki's runner-up finish to Kim Clijsters at the 2009 US Open remains her best Grand Slam performance. She has consolidated her world number one ranking this year with tournament wins at Dubai, Indian Wells, Brussels, Charleston and Copenhagen. However, doubts remain about the Dane's temperament after she flopped again in the Grand Slams with a semi-final loss in Australia followed by a disappointing third round exit at the French Open and a fourth-round defeat at Wimbledon. Since then she has made early exits at Bastad, Toronto and Cincinnati and dropped her father Piotr as her coach.
World ranking: 2 Career Singles titles: 12; Grand Slam singles titles: 0 Best US Open result: Runner-up (2010)
Will be keen to go one better than last year's US Open campaign, which ended in defeat in the final to Kim Clijsters. Reached the final four at the Australian Open in January but exited the French Open in the fourth round and Wimbledon in the third. Since then claimed a 12th career title at Baku.
World ranking: 7 Career Singles titles: 5; Grand Slam singles titles: 1 Best US Open result: Quarter-finals (2009)
Became the first Chinese winner of a Grand Slam when she defeated Francesca Schiavone in the French Open final. That triumph in Paris came hot on the heels of her Australian Open final defeat against Kim Clijsters in January and she'll be keen to get back on track after a disappointing second-round loss at Wimbledon to eventual semi-finalist Sabine Lisicki of Germany.
World ranking: 6 Career Singles titles: 5; Grand Slam singles titles: 1 Best US Open result: 4th round (2009)
Joined the ranks of Grand Slam champions with a straight-sets victory over former world No. 1 Maria Sharapova on July 2 at Wimbledon. Has struggled with a thigh injury since and bowed out in the third round of the WTA hardcourt event in Toronto, but will be vying to cap a breakthrough season with another strong Grand Slam performance.