Rafael Nadal of Spain plays a shot to compatriot Nicolas Almagro during their men's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris, France, May 28, 2015. REUTERS/Vincent Kes

Mirjana Lucic-Baroni of Croatia celebrates after beating Simona Halep of Romania during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris, France, May 27, 2015. REUTERS/Vincent Kessler

Alize Cornet of France plays a shot to Mirjana Lucic-Baroni of Croatia during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris, France, May 29, 2015. REUTERS/Gonzalo Fuentes

Novak Djokovic of Serbia plays a shot to Jarkko Nieminen of Finland during their men's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris, France, May 26, 2015. REUTERS/Pascal Rossignol

Rafael Nadal of Spain plays a shot to compatriot Nicolas Almagro during their men's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris, France, May 28, 2015. REUTERS/Vin

Andrea Hlavackova of the Czech Republic plays a shot to Serena Williams of the U.S. during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris, France, May 26, 2015. REUTERS/Gonzalo Fuentes

Go Soeda of Japan eyes the ball as he prepares to play a shot to Philipp Kohlschreiber of Germany during their men's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris, France, May 24, 2015. REUTERS/Pascal Rossignol

PhotographerVincent KesslerLocationPARIS, FranceReuters / Tuesday, May 26, 2015The shoes of Rafael Nadal of Spain are seen as he jumps to serve to Quentin Halys of France during their men's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris, France, May 26, 2015. REUTERS/Vincent Kessler

Alize Cornet of France celebrates after beating Mirjana Lucic-Baroni of Croatia during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris, France, May 29, 2015. REUTERS/Jean-Paul Pelissier

Caroline Wozniacki of Denmark plays a shot to Karin Knapp of Italy during their women's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris, France, May 26, 2015. REUTERS/Gonzalo Fuentes

Pablo Andujar of Spain plays a shot to Jo-Wilfried Tsonga of France during their men's singles match at the French Open tennis tournament at the Roland Garros stadium in Paris, France, May 29, 2015. REUTERS/Gonzalo Fuentes

Garbine Muguruza of Spain serves to Flavia Pennetta of Italy during their women's singles match during the French Open tennis tournament at the Roland Garros stadium in Paris, France, June 1, 2015. REUTERS/Vincent Kessler

Novak Djokovic of Serbia prepares to serve to Richard Gasquet of France during their men's singles match during the French Open tennis tournament at the Roland Garros stadium in Paris, France, June 1, 2015. REUTERS/Gonzalo Fuentes

Lucie Safarova of the Czech Republic celebrates after defeating Garbine Muguruza of Spain during their women's quarter-final match during the French Open tennis tournament at the Roland Garros stadium in Paris, France, June 2, 2015. REUTERS/Vincent Kessler

Jo-Wilfried Tsonga of France celebrates after defeating Kei Nishikori of Japan during their men's quarter-final match during the French Open tennis tournament at the Roland Garros stadium in Paris, France, June 2, 2015. REUTERS/Jean-Paul Pelissier

Alize Cornet of France argues with the referee during the women's singles match against Elina Svitolina of Ukraine at the French Open tennis tournament at the Roland Garros stadium in Paris, France, May 31, 2015. REUTERS/Pascal Rossignol