Roger Federer of Switzerland hits a return during his men's singles quarterfinal match against Jo-Wilfried Tsonga of France during 2013 Australian Open tennis tournament in Melbourne, Australia, Jan. 23, 2013. Roger Federer won 3-2. (Xinhua/Bai Xue)

Roger Federer of Switzerland celebrates after scoring during his men's singles quarterfinal match against Jo-Wilfried Tsonga of France during 2013 Australian Open tennis tournament in Melbourne, Australia, Jan. 23, 2013. Roger Federer won 3-2. (Xinhua/Bai Xue)

Roger Federer of Switzerland celebrates after winning his men's singles quarterfinal match against Jo-Wilfried Tsonga of France on the tenth day of 2013 Australian Open tennis tournament in Melbourne, Australia, Jan. 23, 2013. Roger Federer won 3-2. (Xinhua/Bai Xue)

Jo-Wilfried Tsonga of France (R) reacts during his men's singles quarterfinal match against Roger Federer of Switzerland on the tenth day of 2013 Australian Open tennis tournament in Melbourne, Australia, Jan. 23, 2013. Jo-Wilfried Tsonga lost 2-3. (Xinhua/Bai Xue)

Roger Federer of Switzerland greets the audience after his men's singles quarterfinal match against Jo-Wilfried Tsonga of France during 2013 Australian Open tennis tournament in Melbourne, Australia, Jan. 23, 2013. Roger Federer won 3-2. (Xinhua/Bai Xue)

Roger Federer of Switzerland greets the audience after his men's singles quarterfinal match against Jo-Wilfried Tsonga of France during 2013 Australian Open tennis tournament in Melbourne, Australia, Jan. 23, 2013. Roger Federer won 3-2. (Xinhua/Bai Xue)

Roger Federer of Switzerland speaks at the post-match press conference after winning his men's singles quarterfinals against Jo-Wilfried Tsonga of France during 2013 Australian Open tennis tournament in Melbourne, Australia, Jan. 23, 2013. Roger Federer won 3-2. (Xinhua/Bai Xue)

Roger Federer of Switzerland speaks at the post-match press conference after winning his men's singles quarterfinals against Jo-Wilfried Tsonga of France during 2013 Australian Open tennis tournament in Melbourne, Australia, Jan. 23, 2013. Roger Federer won 3-2. (Xinhua/Bai Xue)