Argentina's Juan Martin del Potro ended Roger Federer's five-year unbeaten reign at the US Open in five dramatic sets to win his first Grand Slam title.

The 20-year-old sixth seed twice fought back from a set down to win 3-6 7-6 (7-5) 4-6 7-6 (7-4) 6-2.

Del Potro is the first man other than Rafael Nadal to beat Federer in the final of a Grand Slam tournament.

Swiss star Federer, 28, had been going for a record-equalling sixth consecutive title at Flushing Meadows.

American Bill Tild...