Roger Federer of Switzerland celebrates his win over Teymuraz Gabashvili of Russia during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014.(AP Photo/Aaron Favila)
Milos Raonic of Canada appeals a point during his third round loss to Grigor Dimitrov of Bulgaria at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014.(AP Photo/Andrew Brownbill)
Grigor Dimitrov of Bulgaria celebrates his win over Milos Raonic of Canada during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014.(AP Photo/Andrew Brownbill)
Grigor Dimitrov of Bulgaria celebrates his win over Milos Raonic of Canada during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014.(AP Photo/Andrew Brownbill)
Roger Federer of Switzerland signs his autograph for fans after Federer won over Teymuraz Gabashvili of Russia during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014. (AP Photo/Eugene Hoshiko)
Andy Murray of BritaiN rushes for a return shot to Feliciano Lopez of Spain during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014.(AP Photo/Rick Rycroft)
Grigor Dimitrov of Bulgaria, right, is congratulated by Milos Raonic of Canada at the net after he won their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014.(AP Photo/Andrew Brownbill)
Victoria Azarenka of Belarus hits a forehand return to Yvonne Meusburger of Austria during their third match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014.(AP Photo/Aaron Favila))
Stephane Robert of France, right, shakes hands with Martin Klizan of Slovakia at the net after his win in their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014.(AP Photo/Aijaz Rahi)
Stephane Robert of France makes backhand return to Martin Klizan of Slovakia during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014.(AP Photo/Aijaz Rahi)
Stephane Robert of France celebrates his win over Martin Klizan of Slovakia during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014.(AP Photo/Aijaz Rahi)
Stephane Robert of France celebrates his win over Martin Klizan of Slovakia during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014.(AP Photo/Aijaz Rahi)
Elina Svitolina of Ukraine hits a forehand return to Sloane Stephens of the U.S. during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014. (AP Photo/Andrew Brownbill)
Sloane Stephens of the U.S. servers to Elina Svitolina of the Ukraine during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014. (AP Photo/Andrew Brownbill)
Maria Sharapova of Russia hits a backhand return to Alize Cornet of France during their third round match at the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 18, 2014.(AP Photo/Aaron Favila)