Simona Halep of Romania in action against Evgeniya Rodina of Russia during their first round match for the French Open tennis tournament at Roland Garros in Paris, France, 24 May 2015. EPA/ROBERT GHEMENT

A ballgirl in action during the first round match between Simona Halep of Romania and Evgeniya Rodina of Russia for the French Open tennis tournament at Roland Garros in Paris, France, 24 May 2015. EPA/ROBERT GHEMENT

Stan Wawrinka of Switzerland reacts after winning against Marsel Ilhan of Turkey their first round match for the French Open tennis tournament at Roland Garros in Paris, France, 24 May 2015. EPA/ROBERT GHEMENT

Roger Federer of Switzerland in action against Alejandro Falla of Colombia during their first round match for the French Open tennis tournament at Roland Garros in Paris, France, 24 May 2015. EPA/ETIENNE LAURENT

Magda Linette of Poland in action against Flavia Pennetta of Italia during their first round match for the French Open tennis tournament at Roland Garros in Paris, France, 24 May 2015. EPA/ETIENNE LAURENT