Unseeded Mikhail Youzhny caused a huge upset in putting out second seed Rafael Nadal in the last eight of the US Open.
Youzhny has beaten three Spanish seeds at this year's US Open
The 24-year-old Russian, playing in his first-ever Grand Slam quarter-final, beat Nadal 6-3 5-7 7-6 (7-5) 6-1.
The crunch point of a bruising match at Flushing Meadows came when Youzhny saved three set points in the third set before winning it on a tie-break.
World number 54 Youzhny ran away with the fourth set to clinch victory in three hours and 16 minutes.
Nadal is the third Spanish seed Youzhny has beaten at this year's US Open after wins over sixth seed Tommy Robredo and 11th seed David Ferrer.
Despite his defeat, Nadal was happy with the way he had played.
Roddick was the last American man to win a Grand Slam event
"Maybe I played my best match in New York here today," said the 20-year-old.
"I am happy with my tennis, but I was not playing with my best calm in the important moments."
Youzhny will now play Andy Roddick for a place in Sunday's final.
Roddick was in awesome form in Wednesday's night match, storming past fellow ex-champion Lleyton Hewitt in straight sets.
The American blasted his way to a 6-3 7-5 6-4 win.
Fifteenth seed Hewitt tried to stay with Roddick and had a set point in the second set but was ultimately outplayed by a fired-up opponent.
"He came out serving so well and didn't give me too many looks at second serves," said Hewitt, who saw 17 aces whistle past him.
Roddick, who looked very emotional and pumped up after his victory, admitted he was relieved to rediscover his top form.
"I'm in a little bit of shock. It's been a rough six months for me. I haven't played too well," said Roddick, who teamed up with Jimmy Connors earlier this summer.