Li Na of China Ekaterina celebrates a point won against Makarova of Russia during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 19, 2014.(AP Photo/Rick Rycroft)
Li Na of China makes a forehand return to Ekaterina Makarova of Russia during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 19, 2014.(AP Photo/Rick Rycroft)
Ekaterina Makarova of Russia hits a backhand return to Li Na of China during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 19, 2014.(AP Photo/Rick Rycroft)
Li Na of China hits a forehand return to Ekaterina Makarova of Russia during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 19, 2014. (AP Photo/Aijaz Rahi)
Flavia Pennetta of Italy makes a backhand return to Angelique Kerber of Germany during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 19, 2014.(AP Photo/Aaron Favila)
Angelique Kerber of Germany makes a forehand return to Flavia Pennetta of Italy during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 19, 2014.(AP Photo/Eugene Hoshiko)
Flavia Pennetta of Italy celebrates a point won against Agelique Kerber of Germany during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 19, 2014.(AP Photo/Aaron Favila)
Angelique Kerber of Germany reacts between points as she plays Flavia Pennetta of Italy during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 19, 2014.(AP Photo/Eugene Hoshiko)
Flavia Pennetta of Italy bites the net in frustration during her fourth round match against Angelique Kerber of Germany at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 19, 2014.(AP Photo/Eugene Hoshiko)