Roger Federer saw his dream of becoming the first man in 87 years to win six US Opens destroyed by big-swinging Czech Tomas Berdych Wednesday in the Swiss legend's earliest New York defeat in nine years.
The 17-time Grand Slam title winner, bidding to reach his 33rd Grand Slam semi-final, and ninth in a row at the US Open, was beaten 7-6 (7/1), 6-4, 3-6, 6-3 by sixth-seeded Berdych.
"I have got to go back to the drawing board from here. The goal (of winning Wimbledon and getting back to number one) has been achieved, but this is very disappointing," said a despondent Federer.
Berdych was stunned by his triumph.
"It couldn't be better. There's no better moment so far than this one," said the Czech.
It was world number one Federer's worst defeat at the tournament since losing to David Nalbandian in the fourth round in 2003.
Berdych, who went into the quarter-final with a 4-11 record against the world number one, will now face British third seed Andy Murray for a place in Sunday's title match.
"I'll just try to bring something from today and try to add something a little more for my next match," Berdych said.
The 26-year-old Czech has reached the last four in New York for the first time while Saturday will be his first Grand Slam semi-final since he reached the Wimbledon final in 2010.
That was the tournament where he also defeated Federer in the quarter-finals.
In an extraordinary reversal of fortune, Wednesday's clash was Berdych's first appearance in a night match on the main stadium.
Wimbledon champion Federer, by contrast, went into the tie with a perfect 21 wins in his night-time outings.
Federer got off to a rock solid start, breaking in the first game before the Czech hit back at 3-3 and then romped through the tiebreaker.
Federer, 31, was under relentless pressure again in the second set when he was broken twice before the Arthur Ashe Stadium crowd sensed a possible third comeback from two set to love down in three successive Grand Slams as the top seed cut the deficit.
But Berdych steadied himself in the fourth with a break in the eighth game and served out the match to love when Federer's weak service return was his 40th and final unforced error of the contest.
Berdych boasts a 4-2 career winning record over Murray, who reached a second successive US Open semi-final when Croatia's Marin Cilic squandered a set and 5-1 lead to lose 3-6, 7-6 (7/4), 6-2, 6-0.
Murray won 15 of the last 18 games to secure a seventh win in eight meetings with the 12th-seeded Cilic.
"I've had a lot of tough matches -- everyone goes through them. We've seen Rafa, Novak and Roger struggle here," said Murray.
"There is pressure on you to perform well, expectations are high and sometimes you're nervous."
Tearful Andy Roddick said goodbye to the US Open, New York and his career in an emotional fourth-round defeat to Argentina's Juan Martin Del Potro.
The 30-year-old, the last American man to win a Grand Slam event when he claimed the US Open in 2003, had already said this would be the last tournament of a 12-year career which yielded 32 titles and $20 million in prize money.
"I've loved every minute of it -- for the first time in my career I'm not sure what to say," said Roddick, who was in tears -- as was model wife Brooklyn -- as he addressed the crowd after his 6-7 (7/1), 7-6 (7/4), 6-2, 6-4 loss.
Seventh-seeded Del Potro, the champion in 2009, booked a Thursday quarter-final date with defending champion Novak Djokovic.
Djokovic was leading Stanislas Wawrinka 6-4, 6-1, 3-1 when the 18th-seeded Swiss retired after complaining of dizziness and handed the second seed a 14th successive Grand Slam quarter-final place.
His tie against Wawrinka had been held over from Tuesday because of rain with the world number two ahead 2-0 in the first set.
"It was a difficult situation for both of us with the rain yesterday. We were here for 10 or 11 hours, warmed-up and then stopped. It was hard to get ready for a match that way," said Djokovic, the 25-year-old Australian Open champion.
Djokovic has reached his sixth successive US Open quarter-final by dropping just 20 games in four rounds.
Wawrinka has now lost 19 matches in a row against top-10 players.
Djokovic's fellow Serb, eighth seed Janko Tipsarevic, reached his second successive US Open quarter-final.
Tipsarevic brushed past German 19th seed Philipp Kohlschreiber 6-3, 7-6 (7/5), 6-2 and goes on to face Spanish fourth seed David Ferrer for a place in the semi-finals.