Thomas Bach, vice president of the International Olympic Committee (IOC), attends a report session during the 125th IOC session in Buenos Aires, Argentina, Monday, Sept. 9, 2013. (AP Photo/Victor R. Caivano)
Members of the Tokyo 2020 delegation celebrate after Tokyo was awarded the 2020 Olympic Games during the 125th IOC session in Buenos Aires, Argentina, Saturday, Sept. 7, 2013. (AP Photo/Victor R. Caivano)
Juan Martin del Potro, from Argentina, hits the ball during a finals match against John Isner, of the U.S., at the Citi Open tennis tournament, Sunday, Aug. 4, 2013 in Washington. (AP Photo/Alex Brandon)
Camilo Villegas of Colombia, left, and Angel Cabrera of Argentina look down the 6th fairway during the first round of the British Open Golf Championship at Muirfield, Scotland, Thursday July 18, 2013. (AP Photo/Scott Heppell)
Novak Djokovic of Serbia lies on the court after playing a return to Juan Martin Del Potro of Argentina during their men's singles semifinal match at the All England Lawn Tennis Championships in Wimbledon, London, Friday, July 5, 2013. (AP Photo/Alastair Grant)