Spanish second seed Rafael Nadal [Images] suffered a shock defeat in the U.S. Open third round on Saturday, losing 6-4, 4-6, 6-3, 6-1 to American wild card James Blake, the world number 49.

The French Open champion was given a lesson in hard-court tennis by Blake, who equalled his best performance at a grand slam event.

"I can't say enough how this is a dream come true," Blake told the crowd on Arthur Ashe Court.

"I can't believe how well things are going. I am waiting for the alarm clock to go off and I'm going to wake up, but I don't want to."

The 25-year-old American slipped outside the top 200 in April after a year in which he broke vertebrae in his neck, suffered a rare illness and lost his father to cancer.

He returned to form midway through this year, reaching the final in Washington and winning last week's New Haven Open to break back into the top 50.

Against Nadal, he was in scintillating form, smashing 53 winners to his opponent's 29, and hitting 10 aces to the 19-year-old's two.

Nadal, appearing in the third round at Flushing Meadows for the first time, appeared to be gaining control when he hit back to level at one set apiece.

However, Blake continued to attack, keeping the Spaniard pinned well behind the baseline with huge forehands.

After snatching the third set, he romped through the fourth to record one of the best victories of his career.

Blake will play either Frenchman Sebastien Grosjean or 19th seed Tommy Robredo of Spain for a place in the quarter-finals.

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