London Olympics: Federer edges Del Potro in Olympic semifinals

Friday, August 3, 2012 | 4:38 p.m. CDT; updated 5:06 p.m. CDT, Friday, August 3, 2012

WIMBLEDON, England — Roger Federer leaned on the net, exhausted but exhilarated after winning the final set 19-17 to earn his first Olympic singles medal.