Juan Martin del Potro has ended Roger Federer's run of dominance at the US Open, stunning the top-ranked Swiss great in five sets to win in his first Grand Slam final.

The 20-year-old Argentine prevailed 3-6, 7-6 (5), 4-6, 7-6 (4), 6-2 yesterday to snap Federer's streak of five straight US Open titles. The sixth-seeded del Potro had not beaten Federer in their six previous encounters.

Federer had won 40 consecutive matches at Flushing Meadows. He was seeking to become the first man since Bill Tilden in 1920-25 to win the American championship six straight times and the first man since Rod Laver in 1969 to win three straight majors in a season. Del Potro upset No. 3 Rafael Nadal in the semi-finals in straight sets.