NEW YORK, Sept 15 Argentina's Juan Martin del Potro obliterated Roger Federer's 40-match winning streak at the US Open to become the newest member of the Grand Slam champions' club on Monday.

Standing 1.98 metres tall, the Argentine skyscraper left Federer in his shadow as he won 3-6, 7-6, 4-6, 7-6, 6-2 to capture his first Grand Slam crown.

In an electrifying four-hour tussle featuring countless Federer errors, Hawk-Eye disputes, umpire clashes and high-fives with fans, it was del Potro's red-hot forehand that ultimately shone through and denied the Swiss a modern-era record sixth successive US Open title.

After being gifted his third match point with a double fault, an incredulous del Potro kept his eye on the ball as he watched a Federer backhand float long to seal victory.

He dropped his racket and collapsed on to his back, with legs splayed and his hands covering his face, an X-shaped emblem of triumph. Del Potro got back on to his feet as the tears started to flow freely.

The 20-year-old Del Potro earned $1.85 million for his golden run, told the crowd.

French Open and Wimble don champion Federer, who had been bidding for a 16th Grand Slam crown in a final pushed back to Monday, said “I had a great tournament but he was the best.”

The victory at a floodlit Arthur Ashe Stadium allowed del Potro to become the first South American man to triumph in New York since compatriot Guillermo Vilas in 1977. But unlike on that day 32 years ago, Del Potro was not mobbed on court by dozens of fans wanting to get close to a champion.

Instead, Del Potro poured cold water all over his head to ensure he was not dreaming.

The Argentine also became the first man to beat Spaniard Rafael Nadal — whom he beat for the loss of just six games — and Federer back-to-back in a Grand Slam arena.

Federer romped through the opening set and stood two points from taking a two-set lead at 5-4 but the top seed watched in horror as a Hawk-Eye overrule handed del Potro break point.

Convinced the ball-tracking system had picked up the wrong mark, an irritated Federer dropped his serve as the set swung del Potro's way and he roared through the tiebreak 7-5.

It turned out to be the first of many Hawk-Eye decisions to irk the Swiss and after del Potro belatedly challenged a call at the end of the ninth game in the third set, Federer flipped.

Fired up by the exchange, the Swiss punished del Potro in the next game.

Serving to stay in the set, del Potro missed an easy smash to go 0-15. On the next point, a Federer forehand slice bounced on the tape and fell dead.

The del Potro forehand, which proved so devastating in the second set, was once again blazing winners in the fourth and the way he kept spanking the balls brought the crowd alive.

Leading 3-2 with a break, he ended a fast-paced 21-shot rally by curling a forehand in on the run and as the ball dropped in, he kept on running to exchange high-fives with cheering fans in the front row.

Four games later del Potro was left gasping as Federer stood two points from victory but an ace and a forehand thunderbolt got del Potro out of jail and he punched the air in delight.

Almost an hour later, having broken for 2-0 lead in the deciding set with a blistering forehand crosscourt passing shot, del Potro was lying flat on his back in ecstasy.—Reuters