Switzerland's Roger Federer serves the ball during the first round match of the French Open tennis tournament against Slovakia's Lukas Lacko at the Roland Garros stadium, in Paris, France, Sunday, May 25, 2014. (AP Photo/Darko Vojinovic)
Poland's Jerzy Janowicz returns the ball to Dominican Republic's Victor Estrella Burgos during their first round match of the French Open tennis tournament at the Roland Garros stadium, in Paris, France, Sunday, May 25, 2014. (AP Photo/Michel Euler)
Dominican Republic's Victor Estrella Burgos backhands to Poland's Jerzy Janowicz during their first round match of the French Open tennis tournament at the Roland Garros stadium, in Paris, France, Sunday, May 25, 2014. (AP Photo/Michel Euler)
Dominican Republic's Victor Estrella Burgos backhands to Poland's Jerzy Janowicz during their first round match of the French Open tennis tournament at the Roland Garros stadium, in Paris, France, Sunday, May 25, 2014. (AP Photo/Michel Euler)
Grace Min of the U.S, returns the ball to Spain's Garbine Muguruza during the first round match of the French Open tennis tournament at the Roland Garros stadium, in Paris, France, Sunday, May 25, 2014. (AP Photo/Michel Euler)
John Isner of the U.S. clenches his fist during the first round match of the French Open tennis tournament against France's Pierre-Hugues Herbert at the Roland Garros stadium, in Paris, France, Sunday, May 25, 2014. (AP Photo/David Vincent)
Germany's Angelique Kerber reacts as she plays Poland's Katarzyna Piter during the first round match of the French Open tennis tournament at the Roland Garros stadium, in Paris, France, Sunday, May 25, 2014. (AP Photo/David Vincent)
Switzerland's Belinda Bencic returns the ball during the first round match of the French Open tennis tournament against Venus Williams of the US at the Roland Garros stadium, in Paris, France, Sunday, May 25, 2014. (AP Photo/David Vincent)