Melanie Oudin of the U.S. eyes the ball during her women's singles match against Zheng Jie of China at the French Open tennis tournament at the Roland Garros stadium in Paris May 30, 2013. REUTERS/Stephane Mahe (FRANCE - Tags: SPORT TENNIS)

Zheng Jie of China hits a return to Melanie Oudin of the U.S. during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris May 30, 2013. REUTERS/Stephane Mahe (FRANCE - Tags: SPORT TENNIS)

Melanie Oudin of the U.S. hits a return to Zheng Jie of China during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris May 30, 2013. REUTERS/Stephane Mahe (FRANCE - Tags: SPORT TENNIS)

Zheng Jie of China reacts during her women's singles match against Melanie Oudin of the U.S. at the French Open tennis tournament at the Roland Garros stadium in Paris May 30, 2013. REUTERS/Stephane Mahe (FRANCE - Tags: SPORT TENNIS)

Melanie Oudin of the U.S. hits a return to Zheng Jie of China during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris May 30, 2013. REUTERS/Stephane Mahe (FRANCE - Tags: SPORT TENNIS)

Zheng Jie of China serves to Melanie Oudin of the U.S. during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris May 30, 2013. REUTERS/Stephane Mahe (FRANCE - Tags: SPORT TENNIS)

Zheng Jie of China eyes the ball during her women's singles match against Melanie Oudin of the U.S. at the French Open tennis tournament at the Roland Garros stadium in Paris May 30, 2013. REUTERS/Stephane Mahe (FRANCE - Tags: SPORT TENNIS)

Zheng Jie of China serves to Vesna Dolonc of Serbia during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris May 27, 2013. REUTERS/Gonzalo Fuentes (FRANCE - Tags: SPORT TENNIS)

Zheng Jie of China eyes the ball during her women's singles match against Vesna Dolonc of Serbia at the French Open tennis tournament at the Roland Garros stadium in Paris May 27, 2013. REUTERS/Gonzalo Fuentes (FRANCE - Tags: SPORT TENNIS)

Vesna Dolonc of Serbia rubs her eye during her women's singles match against Zheng Jie of China at the French Open tennis tournament at the Roland Garros stadium in Paris May 27, 2013. REUTERS/Gonzalo Fuentes (FRANCE - Tags: SPORT TENNIS)

Vesna Dolonc of Serbia reacts during her women's singles match against Zheng Jie of China at the French Open tennis tournament at the Roland Garros stadium in Paris May 27, 2013. REUTERS/Gonzalo Fuentes (FRANCE - Tags: SPORT TENNIS)

Zheng Jie of China celebrates a point against Vesna Dolonc of Serbia during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris May 27, 2013. REUTERS/Gonzalo Fuentes (FRANCE - Tags: SPORT TENNIS)

Zheng Jie of China hits a return to Vesna Dolonc of Serbia during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris May 27, 2013. REUTERS/Gonzalo Fuentes (FRANCE - Tags: SPORT TENNIS)

Vesna Dolonc of Serbia hits a return to Zheng Jie of China during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris May 27, 2013. REUTERS/Gonzalo Fuentes (FRANCE - Tags: SPORT TENNIS)

Vesna Dolonc of Serbia hits a return to Zheng Jie of China during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris May 27, 2013. REUTERS/Gonzalo Fuentes (FRANCE - Tags: SPORT TENNIS)

China's Jie Zheng returns a shot to to Russia's Nadia Petrova at the Sony Open tennis tournament in Key Biscayne, Florida March 22, 2013. REUTERS/Andrew Innerarity (UNITED STATES - Tags: SPORT TENNIS) 

Ksenia Pervak of Kazakhstan returns a shot against Jie Zheng of China during their match at the BNP Paribas Open WTA tennis tournament in Indian Wells, California, March 6, 2013. REUTERS/Danny Moloshok (UNITED STATES - Tags: SPORT TENNIS) 

Jie Zheng of China serves against Ksenia Pervak of Kazakhstan during their match at the BNP Paribas Open WTA tennis tournament in Indian Wells, California, March 6, 2013. REUTERS/Danny Moloshok (UNITED STATES - Tags: SPORT TENNIS) 

Jie Zheng of China returns a shot against Ksenia Pervak of Kazakhstan during their match at the BNP Paribas Open WTA tennis tournament in Indian Wells, California, March 6, 2013. REUTERS/Danny Moloshok (UNITED STATES - Tags: SPORT TENNIS) 

Anastasia Rodionova of Australia reacts during her women's match against Zheng Jie of China at the Qatar Open tennis tournament in Doha February 11, 2013. REUTERS/Fadi Al-Assaad (QATAR - Tags: SPORT TENNIS) 

Anastasia Rodionova of Australia reacts against Zheng Jie of China during their women's match at the Qatar Open tennis tournament in Doha February 11, 2013. REUTERS/Fadi Al-Assaad (QATAR - Tags: SPORT TENNIS) 

Zheng Jie of China returns the ball to Anastasia Rodionova of Australia during their women's Qatar Open tennis match in Doha February 11, 2013. REUTERS/Fadi Al-Assaad (QATAR - Tags: SPORT TENNIS) 

Zheng Jie of China returns the ball to Anastasia Rodionova of Australia during their women's Qatar Open tennis match in Doha February 11, 2013. REUTERS/Fadi Al-Assaad (QATAR - Tags: SPORT TENNIS) 

Anastasia Rodionova of Australia returns the ball to Zheng Jie of China during their women's Qatar Open tennis match in Doha February 11, 2013. REUTERS/Fadi Al-Assaad (QATAR - Tags: SPORT TENNIS) 

Anastasia Rodionova of Australia returns the ball to Zheng Jie of China during their women's Qatar Open tennis match in Doha February 11, 2013. REUTERS/Fadi Al-Assaad (QATAR - Tags: SPORT TENNIS) 

Anastasia Rodionova of Australia celebrates scoring against Zheng Jie of China during their women's Qatar Open tennis match in Doha February 11, 2013. REUTERS/Fadi Al-Assaad (QATAR - Tags: SPORT TENNIS) 

Zheng Jie of China returns the ball to Anastasia Rodionova of Australia during their women's Qatar Open tennis match in Doha February 11, 2013. REUTERS/Fadi Al-Assaad (QATAR - Tags: SPORT TENNIS) 

Anastasia Rodionova of Australia returns the ball to Zheng Jie of China during their women's Qatar Open tennis match in Doha February 11, 2013. REUTERS/Fadi Al-Assaad (QATAR - Tags: SPORT TENNIS) 

Anastasia Rodionova of Australia returns the ball to Zheng Jie of China during their women's Qatar Open tennis match in Doha February 11, 2013. REUTERS/Fadi Al-Assaad (QATAR - Tags: SPORT TENNIS) 

Anastasia Rodionova of Australia returns the ball to Zheng Jie of China during their women's Qatar Open tennis match in Doha February 11, 2013. REUTERS/Fadi Al-Assaad (QATAR - Tags: SPORT TENNIS) 

Julia Goerges of Germany hits a return to Zheng Jie of China during their women's singles match at the Australian Open tennis tournament in Melbourne, January 18, 2013. REUTERS/Navesh Chitrakar (AUSTRALIA - Tags: SPORT TENNIS)

Julia Goerges of Germany reacts during her women's singles match against Zheng Jie of China at the Australian Open tennis tournament in Melbourne, January 18, 2013. REUTERS/Navesh Chitrakar (AUSTRALIA - Tags: SPORT TENNIS)

Zheng Jie of China hits a return to Julia Goerges of Germany during their women's singles match at the Australian Open tennis tournament in Melbourne, January 18, 2013. REUTERS/Navesh Chitrakar (AUSTRALIA - Tags: SPORT TENNIS)

Zheng Jie of China hits a return to Julia Goerges of Germany during their women's singles match at the Australian Open tennis tournament in Melbourne, January 18, 2013. REUTERS/Navesh Chitrakar (AUSTRALIA - Tags: SPORT TENNIS)

Julia Goerges of Germany hits a return to Zheng Jie of China during their women's singles match at the Australian Open tennis tournament in Melbourne, January 18, 2013. REUTERS/Navesh Chitrakar (AUSTRALIA - Tags: SPORT TENNIS)

Julia Goerges of Germany celebrates defeating Zheng Jie of China in their women's singles match at the Australian Open tennis tournament in Melbourne, January 18, 2013. REUTERS/Navesh Chitrakar (AUSTRALIA - Tags: SPORT TENNIS)

Julia Goerges of Germany celebrates defeating Zheng Jie of China in their women's singles match at the Australian Open tennis tournament in Melbourne, January 18, 2013. REUTERS/Navesh Chitrakar (AUSTRALIA - Tags: SPORT TENNIS)

Julia Goerges of Germany celebrates defeating Zheng Jie of China in their women's singles match at the Australian Open tennis tournament in Melbourne, January 18, 2013. REUTERS/Navesh Chitrakar (AUSTRALIA - Tags: SPORT TENNIS)

Samantha Stosur of Australia leaves the court after losing her women's singles match to Zheng Jie of China at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Zheng Jie of China celebrates defeating Samantha Stosur of Australia in their women's singles match at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Zheng Jie of China celebrates during her women's singles match against Samantha Stosur of Australia at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Zheng Jie of China celebrates defeating Samantha Stosur of Australia in their women's singles match at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Zheng Jie of China reacts during their women's singles match against Samantha Stosur of Australia at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Samantha Stosur of Australia reacts during her women's singles match against Zheng Jie of China at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Samantha Stosur of Australia reacts during her women's singles match against Zheng Jie of China at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Samantha Stosur of Australia hits a return to Zheng Jie of China during their women's singles match at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Samantha Stosur of Australia adjusts her glasses during her women's singles match against Zheng Jie of China at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Samantha Stosur of Australia hits a return to Zheng Jie of China during their women's singles match at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Samantha Stosur of Australia hits a return to Zheng Jie of China during their women's singles match at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Zheng Jie of China reacts during her women's singles match against Samantha Stosur of Australia at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Zheng Jie of China hits a return to Samantha Stosur of Australia during their women's singles match at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Zheng Jie of China hits a return to Samantha Stosur of Australia during their women's singles match at the Australian Open tennis tournament in Melbourne, January 16, 2013. REUTERS/Daniel Munoz (AUSTRALIA - Tags: SPORT TENNIS)

Zheng Jie of China towels off in her loss to Victoria Azarenka of Belarus during their match at the US Open women's singles tennis tournament in New York, August 31, 2012. REUTERS/Bill Kostroun (UNITED STATES - Tags: SPORT TENNIS) 

Zheng Jie of China hits a return to Victoria Azarenka of Belarus during their match at the US Open women's singles tennis tournament in New York, August 31, 2012. REUTERS/Bill Kostroun (UNITED STATES - Tags: SPORT TENNIS) 

Victoria Azarenka of Belarus falls to the court against Zheng Jie of China during their match at the US Open women's singles tennis tournament in New York, August 31, 2012. REUTERS/Bill Kostroun (UNITED STATES - Tags: SPORT TENNIS) 

Victoria Azarenka of Belarus serves to Zheng Jie of China during their match at the US Open women's singles tennis tournament in New York, August 31, 2012. REUTERS/Bill Kostroun (UNITED STATES - Tags: SPORT TENNIS) 

Victoria Azarenka of Belarus hits a return to Zheng Jie of China during their match at the US Open women's singles tennis tournament in New York, August 31, 2012. REUTERS/Bill Kostroun (UNITED STATES - Tags: SPORT TENNIS) 

Serena Williams of the U.S. celebrates after defeating Zheng Jie of China in their women's singles tennis match at the Wimbledon tennis championships in London June 30, 2012. REUTERS/Stefan Wermuth (BRITAIN - Tags: SPORT TENNIS)

Serena Williams of the U.S. celebrates after defeating Zheng Jie of China in their women's singles tennis match at the Wimbledon tennis championships in London June 30, 2012. REUTERS/Stefan Wermuth (BRITAIN - Tags: SPORT TENNIS)

Serena Williams of the U.S. (R) prepares to shake hands with Zheng Jie of China after defeating her in their women's singles tennis match at the Wimbledon tennis championships in London June 30, 2012. REUTERS/Stefan Wermuth (BRITAIN - Tags: SPORT TENNIS)