Roger Federer clinched the first singles medal of his career Friday, August 3 when he won an Olympic marathon, taking the third set 19-17, the Associated Press reported.

Federer outlasted Juan Martin del Potro of Argentina in the semifinals 3-6, 7-6 (5), 19-17 in 4 hours, 26 minutes.

Federer converted only two of 13 break-point chances, the second coming in the next-to-last game.

A four-time Olympian, Federer clinched at least a silver. On Sunday he'll play in the final against the winner of the second semifinal between No. 2-seeded Novak Djokovic of Serbia and No. 3 Andy Murray of Britain.

In 2008, Federer and Swiss teammate Stanislas Wawrinka won the gold in doubles. But Federer had been 0 for 3 in Olympic singles, the biggest hole in a resume that includes a record 17 Grand Slam titles.