Taylor Townsend, of the U.S, returns the ball to France's Alize Cornet during the second round match of the French Open tennis tournament at the Roland Garros stadium, in Paris, France, Wednesday, May 28, 2014. (AP Photo/Darko Vojinovic)
Germany's Andrea Petkovic returns the ball to Switzerland's Stefanie Voegele during their second round match of the French Open tennis tournament at the Roland Garros stadium, in Paris, France, Thursday, May 29, 2014. (AP Photo/David Vincent)
Germany's Andrea Petkovic returns the ball to Switzerland's Stefanie Voegele during their second round match of the French Open tennis tournament at the Roland Garros stadium, in Paris, France, Thursday, May 29, 2014. (AP Photo/David Vincent)
Serbia's Anna Ivanovic returns the ball during the second round match of the French Open tennis tournament against Ukraine's Elina Svitolina at the Roland Garros stadium, in Paris, France, Thursday, May 29, 2014. (AP Photo/Darko Vojinovic)
Serbia's Anna Ivanovic returns the ball during the second round match of the French Open tennis tournament against Ukraine's Elina Svitolina at the Roland Garros stadium, in Paris, France, Thursday, May 29, 2014. (AP Photo/Darko Vojinovic)
Serbia's Anna Ivanovic returns the ball during the second round match of the French Open tennis tournament against Ukraine's Elina Svitolina at the Roland Garros stadium, in Paris, France, Thursday, May 29, 2014. (AP Photo/Darko Vojinovic)
Serbia's Anna Ivanovic serves the ball during the second round match of the French Open tennis tournament against Ukraine's Elina Svitolina at the Roland Garros stadium, in Paris, France, Thursday, May 29, 2014. (AP Photo/Darko Vojinovic)