Ashleigh Barty of Australia serves to Serena Williams of the U.S. during the first round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 13, 2014.(AP Photo/Eugene Hoshiko)
Serena Williams of the United States hits a forehand return to Ashleigh Barty of Australia during their first round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 13, 2014.(AP Photo/Aaron Favila)
Serena Williams of the United States hits a forehand return to Ashleigh Barty of Australia during their first round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 13, 2014.(AP Photo/Aaron Favila)
Serena Williams of the United States stretches for a return to Ashleigh Barty of Australia at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 13, 2014.(AP Photo/Eugene Hoshiko)