** FILE ** Roger Federer of Switzerland leans on the net after he defeated Juan Martin del Potro of Argentina at the All England Lawn Tennis Club in Wimbledon, London at the 2012 Summer Olympics, Friday, Aug. 3, 2012. (AP Photo/Elise Amendola)

Photo by: Elise Amendola

** FILE ** Roger Federer of Switzerland leans on the net after he defeated Juan Martin del Potro of Argentina at the All England Lawn Tennis Club in Wimbledon, London at the 2012 Summer Olympics, Friday, Aug. 3, 2012. (AP Photo/Elise Amendola)