Li Na of China celebrates her win over Belinda Bencic of Switzerland in their second round match at the Australian Open tennis championship in Melbourne, Australia, Wednesday, Jan. 15, 2014.(AP Photo/Aaron Favila)
Belinda Bencic of Switzerland makes a backhand return to Li Na of China during their second round match at the Australian Open tennis championship in Melbourne, Australia, Wednesday, Jan. 15, 2014.(AP Photo/Aaron Favila)
Li Na of China makes a forehand return to Belinda Bencic of Switzerland during their second round match at the Australian Open tennis championship in Melbourne, Australia, Wednesday, Jan. 15, 2014.(AP Photo/Aaron Favila)
Roger Federer of Switzerland makes a backhand return to James Duckworth of Australia during their first round match at the Australian Open tennis championship in Melbourne, Australia, Tuesday, Jan. 14, 2014.(AP Photo/Eugene Hoshiko)