Gallery: 
 

AP Argentina's Juan Martin Del Potro selects a ball to serve to Ryan Harrison in the third round of play at the 2012 US Open tennis tournament, Friday, - Photo

Argentina's Juan Martin Del Potro selects a ball to serve to Ryan Harrison in the third round of play at the 2012 US Open tennis tournament, Friday,

Friday August 31, 09:19 PM
Argentina's Juan Martin Del Potro selects a ball to serve to Ryan Harrison in the third round of play at the 2012 US Open tennis tournament, Friday, Aug. 31, 2012, in New York. (AP Photo/Paul Bereswill)