Russia's Elena Dementieva returns a ball to US Serena Williams during their semi final match on Day 10 at the 2009 Wimbledon tennis championships at the All England Club on July 2, 2012.
Caroline Wozniacki of Denmark volleys against Edina Gallovitis of Romania at the Sony Erricsson WTA Tour's Pilot Pen Tennis on August 25, 2009 in New Haven, Connecticut.
Kim Clijsters of Belgium celebrates beating Vera Zvonareva of Russia during their semi-final women's singles match on the eleventh day of the Australian Open tennis tournament in Melbourne on January 27, 2011. Clijsters won 6-3, 6-3
Caroline Wozniacki of Denmark volleys against Edina Gallovitis of Romania at the Sony Erricsson WTA Tour's Pilot Pen Tennis on August 25, 2009 in New Haven, Connecticut.
Serena Williams of the US plays against Russia's Elena Dementieva during a Women's Semi-Final match in the 2009 Wimbledon Tennis Championships at the All England Tennis Club, in southwest London, on July 2, 2009
Li Na of China plays a stroke during her women's singles semi-final match against Caroline Wozniacki of Denmark on the eleventh day of the Australian Open tennis tournament in Melbourne on January 27, 2011. Li Na won 3-6. 7-5. 6-3.
Tennis player Caroline Wozniacki of Denmark (R) signs the handle of a tennis raquet as Kim Clijsters of Belgium (L) grips hers during a meeting with Thai Prime Minister Abhisit Vejjajiva (unseen) at Government House in Bangkok on December 30, 2010. Wozniacki and Clijsters will play an exhibition tennis match on January 1, 2011 in Hua Hin.