Second seed Rafael Nadal was knocked out of the U.S. Open by an inspired Mikhail Youzhny, falling 6-3, 5-7, 7-6, 6-1 in the quarter-finals on Wednesday under a flurry of winners by the unseeded Russian.
The 54th-ranked Youzhny, whose main claim to fame was a victory from two sets down in the fifth and decisive Davis Cup final match against France in 2002, rose to the occasion again in his first Grand Slam quarter-final.
Hitting out from both wings, the 24-year-old Youzhny set up angles for winners and found the mark with amazing consistency, cracking 49 winners against just 23 for the French Open champion in registering the biggest shock of the tournament so far.
"It was a very tough match," Youzhny said after his three hour 16-minute victory. "I can't believe I beat Rafael in four sets."
The Russian turned around the match in the third set when he battled back from 0-40 to save three set points before holding serve for 5-5 and forcing a tiebreaker, which he won 7-5 by winning the last three points.
Youzhny will face a former Open champion in the semi-finals as he awaits the winner of the quarter-final between Andy Roddick of the U.S. and Australia's Lleyton Hewitt.
Nadal, 20, had been hoping to reach his first U.S. Open final for a possible third successive Grand Slam showdown against world number one Roger Federer.
Nadal won the French Open final over Federer, while the Swiss top seed beat the Spaniard to the Wimbledon crown.
SUNNY SKIES
Federer took his next step toward claiming a third straight U.S. Open title by joining women's top seed Amelie Mauresmo in posting easy straight-sets wins under sunny skies at Flushing Meadows.
After rain wiped out nearly all of Tuesday's matches, clear skies and cool temperatures greeted the players as tournament officials scrambled to make up for lost time.
Federer won the first three games of his fourth-round match without losing a point against Marc Gicquel on his way to a 6-3, 7-6, 6-3 victory over the Frenchman.
"That was great, that got me going," Federer, who has yet to lose a set, said about his awesome start. "I think that was even a key to the match."
Federer blasted 15 aces and had 42 winners but the 79th-ranked Gicquel produced a respectable showing by committing only 22 unforced errors, seven fewer than the Swiss.
In the quarter-finals, eight-times Grand Slam champion Federer will play fifth-seeded American James Blake, a 6-4 6-3, 6-1 winner against 12th seed Tomas Berdych of the Czech Republic.
On the women's side, Mauresmo rolled into the semi-finals with an easy 6-2, 6-3 victory over Russian Dinara Safina, while second seed Justine Henin-Hardenne set up a semi-final showdown with Serbian Jelena Jankovic by battling past Lindsay Davenport 6-4, 6-4 in a match between former champions.
Mauresmo, who will face third seed Maria Sharapova or France's Tatiana Golovin in the semi-finals, broke Safina's serve all four times in the first set.
IN CONTROL
"It's good to be able to be in control, feel good on the court, and really get a good rhythm," Mauresmo said after the 62-minute affair. "Today I felt pretty good on the court."
Mauresmo motored in the second set, firing 10 winners while never losing serve.
"It was completely not my day today," said Safina, who repeatedly whacked her racket on the court in disgust.
In other matches, Russian Nikolay Davydenko completed his rain-delayed 6-1, 5-7, 6-3, 6-0 fourth-round victory over British teenager Andy Murray, while 14th seed Tommy Haas edged former champion Marat Safin, Safina's brother, 4-6, 6-3, 2-6, 6-2, 7-6.
Davydenko needed only 36 minutes to whip Murray 6-0 during the one set played on Wednesday after rain interrupted their match a day earlier.
"I never played against someone who's played a set as well as that," said Murray.