Guillermo Garcia-Lopez of Spain returns a shot during match against Leonardo Mayer of Argentina at the the City Open tennis tournament, Monday, July 30, 2012, in Washington. (AP Photo/Carolyn Kaster)

Magdalena Rybarikova, of Slovakia, returns a shot during a match against Chanelle Scheepers, of South Africa, at the City Open tennis tournament, Monday, July 30, 2012, in Washington. Rybarikova won 6-2, 6-1. (AP Photo/Carolyn Kaster)

Magdalena Rybarikova, of Slovakia, returns a shot during a match against Chanelle Scheepers, of South Africa, at the City Open tennis tournament, Monday, July 30, 2012, in Washington. Rybarikova won 6-2, 6-1. (AP Photo/Carolyn Kaster)

Chanelle Scheepers, of South Africa, returns a shot during a match against Magdalena Rybarikova, of Slovakia, at the City Open tennis tournament, Monday, July 30, 2012, in Washington. Rybarikova won 6-2, 6-1. (AP Photo/Carolyn Kaster)

Sandra Zahlavova, of the Czech Republic, stretches to return a shot against Edina Gallovits-Hall, of Romania, during a match at the City Open tennis tournament, Monday, July 30, 2012, in Washington. Gallovits-Hall won 7-5, 4-6, 6-3. (AP Photo/Carolyn Kaster)

Edina Gallovits-Hall, of Romania, returns a shot against Sandra Zahlavova, of the Czech Republic, during a match at the City Open tennis tournament, Monday, July 30, 2012, in Washington. Gallovits-Hall won 7-5, 4-6, 6-3. (AP Photo/Carolyn Kaster)

Sesil Karatantcheva of Kazakhstan returns a shot during a match against Sloane Stephens of the United States at the the City Open tennis tournament, Monday, July 30, 2012, in Washington. (AP Photo/Carolyn Kaster)

Melanie Oudin returns a shot during a match against Aravane Rezai, of France, at the City Open tennis tournament, Monday, July 30, 2012, in Washington. (AP Photo/Carolyn Kaster)

Melanie Oudin returns a shot during a match against Aravane Rezai, of France, at the City Open tennis tournament, Monday, July 30, 2012, in Washington. (AP Photo/Carolyn Kaster)

Aravane Rezai, of France, returns a shot during a match against Melanie Oudin at the City Open tennis tournament, Monday, July 30, 2012, in Washington. (AP Photo/Carolyn Kaster)

Sloane Stephens of the United States returns a shot during a match against Sesil Karatantcheva of Kazakhstan at the the City Open tennis tournament, Monday, July 30, 2012, in Washington. (AP Photo/Carolyn Kaster)

Sloane Stephens of the United States returns a shot during a match against Sesil Karatantcheva of Kazakhstan at the the City Open tennis tournament, Monday, July 30, 2012, in Washington. (AP Photo/Carolyn Kaster)

Sandra Zahlavova, of the Czech Republic, reacts to losing a point against Edina Gallovits-Hall, of Romania, during a match at the City Open tennis tournament, Monday, July 30, 2012, in Washington. Gallovits-Hall won 7-5, 4-6, 6-3. (AP Photo/Carolyn Kaster)

Chanelle Scheepers, of South Africa, reaches to return a shot during a match against Magdalena Rybarikova, of Slovakia, at the City Open tennis tournament, Monday, July 30, 2012, in Washington. Rybarikova won 6-2, 6-1. (AP Photo/Carolyn Kaster)