Roger Federer of Switzerland celebrates after winning his men's singles first round match against Pablo Carreno-Busta of Spain during the 2013 French Open tennis tournament at Roland Garros in Paris, France, on May 26, 2013. Roger Federer won 3-0. (Xinhua/Bai Xue)

Roger Federer of Switzerland serves during his men's singles first round match against Pablo Carreno-Busta of Spain during the 2013 French Open tennis tournament at Roland Garros in Paris, France, on May 26, 2013. Roger Federer won 3-0. (Xinhua/Bai Xue)

Roger Federer of Switzerland hits a return during his men's singles first round match against Pablo Carreno-Busta of Spain during the 2013 French Open tennis tournament at Roland Garros in Paris, France, on May 26, 2013. Roger Federer won 3-0. (Xinhua/Bai Xue)

Roger Federer of Switzerland celebrates after winning his men's singles first round match against Pablo Carreno-Busta of Spain during the 2013 French Open tennis tournament at Roland Garros in Paris, France, on May 26, 2013. Roger Federer won 3-0. (Xinhua/Bai Xue)

Roger Federer of Switzerland greetings to crowds after winning his men's singles first round match against Pablo Carreno-Busta of Spain during the 2013 French Open tennis tournament at Roland Garros in Paris, France, on May 26, 2013. Roger Federer won 3-0. (Xinhua/Bai Xue)