Silvia Soler-Espinosa of Spain in action against Pauline Parmentier of France during their first round match for the French Open tennis tournament at Roland Garros in Paris, France, 26 May 2015. EPA/CAROLINE BLUMBERG

Petra Kvitova of Czech Republic in action against Marina Erakovic of New Zealand during their first round match for the French Open tennis tournament at Roland Garros in Paris, France, 26 May 2015. EPA/YOAN VALAT

Caroline Wozniacki of Denmark in action against Karin Knapp of Italy during their first round match for the French Open tennis tournament at Roland Garros in Paris, France, 26 May 2015. EPA/ROBERT GHEMENT

Qiang Wang of China in action against Francesca Schiavone of Italy during their first round match for the French Open tennis tournament at Roland Garros in Paris, France, 26 May 2015. EPA/ETIENNE LAURENT

Karin Knapp of Italy in action against Caroline Wozniacki of Denmark during their first round match for the French Open tennis tournament at Roland Garros in Paris, France, 26 May 2015. EPA/ROBERT GHEMENT