1, having enjoyed an impressive 2009 season in which she won the Australian Open and Wimbledon (she would successfully defend both titles this year) and reclaimed the World No.

[2] However, shortly after winning Wimbledon, Serena Williams would injure her foot at a German restaurant where she was celebrating her victory, but it didn't deter her from playing in an exhibition match against Kim Clijsters in front of a world-record tennis crowd that same week.

[3] The foot injury ended up being very serious enough to necessitate surgery,[4] and as a result she missed the rest of the season and would not return to top-level tennis until June 2011.

1 Justine Henin announced her comeback to the WTA Tour in September last year, in the aftermath of Kim Clijsters' victory at the 2009 US Open.

She then participated at her first French Open since 2007, where she was defeated in the fourth round by eventual finalist Samantha Stosur, ending a 24-match winning streak at the tournament dating back to 2005.

She was able to reach the semi-finals at the Brisbane International and the Rome Masters,[13] but those would be her best results in the first half of the season, as she dropped out of the WTA's Top 50 for the first time since 2005 with a second round loss to Anastasija Sevastova at Indian Wells.

[16] However, Ivanovic would begin to turn her season around at the 2010 Western & Southern Financial Group Women's Open, entering the tournament having lost 17 of her last 29 matches dating back to August 2009 and having dropped to World No.

[18] With no rankings points to defend for the remainder of the year, Ivanovic reached the fourth round of the US Open, the first time she had gotten that far at a Grand Slam tournament since Wimbledon in 2009.

She defeated Ekaterina Makarova,[19] Zheng Jie[20] and Virginie Razzano before being crushed by defending and eventual champion Kim Clijsters in the fourth round.

Ivanovic continued to maintain her recent good form after the US Open; she was able to reach the quarter-finals in Beijing where she was defeated by Caroline Wozniacki, who eventually replaced Serena Williams as the new World No.