Second-seed Rafael Nadal crashed out of the US Open on Wednesday losing 6-3, 5-7, 7-6 (7/5), 6-1 to an inspired Mikhail Youzhny of Russia in a quarter-final match.
The unseeded Youzhny will play either Andy Roddick of the United States or Lleyton Hewitt of Australia for a place in the final.
A bruising encounter turned on a tense third set tie-break which the world 54th ranked Youzhny won 7/5 after a series of gruelling rallies.
Playing inspired tennis he ran away into a 5-0 lead in the fourth set leaving Nadal shaking his head in disbelief and with a mountain to climb.
The 20-year-old Spaniard managed to win one game and had a break point in the next, but Youzhny held firm and he converted his first match point when Nadal hit a forehand inches wide.
Youzhny punched the air in delight before enacting his trademark victory gesture which involves placing his racquet on his head and doing a military salute to all four corners of the stadium.
"It was a very tough match. I can't believe I beat Rafa in four sets," said the 24-year-old Muscovite, who won the clinching rubber for his country in the Davis Cup final against France in Paris in 2002 but who has struggled to confirm his potential since then.
"When we started all the crowd was for Rafa because he was the favoirite, but I hope I have managed to change their opinion," he said.
Nadal, the French Open champion and Wimbledon runner-up, had been seeded to meet top seed and defending champion Roger Federer in Sunday's final.
The two met in both the French Open and Wimbledon finals which they shared with one win each.
Nadal said that he had played his best tennis to date in New York. "But he was playing unbelievable, especially in the beginning.
"I just did not play well at the big moments and I didn't have the best of luck.
"I had a big chance to get into the semi-finals and I've lost an opportunity.
"I can't say I'm happy with my tournament. I am number two in the world and I lost in the last eight.
"I've improved my tennis here, but I'm disappointed all the same. My special goal is next year in Australia, I have four months."
Youzhny made it two Russians into the last eight following Nikolay Davydenko's four sets win over Britain's Andy Murray.
But they came up short on what would have been an unprecedented hat-trick as Marat Safin dropped a five-setter to Tommy Haas of Germany.