Juan Martin del Potro of Argentina makes a backhand return to Rhyne Williams of the U.S. during their first round match at the Australian Open tennis championship in Melbourne, Australia, Tuesday, Jan. 14, 2014. (AP Photo/Andrew Brownbill)
Juan Martin del Potro of Argentina serves to Rhyne Williams of the U.S. during their first round match at the Australian Open tennis championship in Melbourne, Australia, Tuesday, Jan. 14, 2014. (AP Photo/Andrew Brownbill)
Supporters of Andy Murray of Britain cheer during his first round match against Go Soeda of Japan at the Australian Open tennis championship in Melbourne, Australia, Tuesday, Jan. 14, 2014.(AP Photo/Rick Rycroft)
Andy Murray of Britain makes a forehand return to Go Soeda of Japan during their first round match at the Australian Open tennis championship in Melbourne, Australia, Tuesday, Jan. 14, 2014.(AP Photo/Rick Rycroft)