A little-known left-hander from Luxembourg destroyed the US Open dream of American Andy Roddick on Tuesday.
Gilles Muller, a 22-year-old playing at Flushing Meadows for the first time, produced the tennis of his life to beat the 2003 champion and fourth seed 7-6 7-6 7-6 in a huge first round upset on Roddick's 23rd birthday.
"I have no idea (how I did it)," said Muller, who beat Rafael Nadal in the second round at Wimbledon in June.
Representing a nation with a population of less than half a million, Muller brutally exposed the weakness of Roddick's backhand and repelled his 150 mph serve with a remarkable 65 outright winners.
It left the American dumbfounded in front of an expectant crowd at the Arthur Ashe Court.
"I don't really remember a loss where I've felt this bad afterwards," a dazed Roddick said. "I love playing here.
"I'm a little bit in shock right now to be honest."
Having trailed 5-2 in the first set, Muller won the respective tiebreaks 7-4, 10-8 and 7-1 against the man with the hardest serve in the sport's history.
In contrast to Roddick, men's top seed Roger Federer picked up where he left off last year, starting his title defence with a ruthless first-round defeat of Czech Ivo Minar.
A year ago, Federer crushed Lleyton Hewitt in the final and the Swiss top seed's 61-minute, 6-1 6-1 6-1 victory over Minar sent out an ominous warning to those who covet his US crown.
Women's second seed Lindsay Davenport, third seed Amelie Mauresmo and French Open champion Justine Henin-Hardenne also advanced to the second round without dropping a set.
However, the player Federer beat in last year's semi-finals, Briton Tim Henman, made a painful exit.
Compatriot Greg Rusedski also lost but a third Briton, teenager Andy Murray, progressed despite throwing up on court during his five-set win.
World number one Davenport had to work hard for a 6-4 6-4 win over a determined Li Na of China in the first evening session match.
"It was a good first match to get under my belt, she is a very good player," Davenport said.
"I just hope I can get better as the tournament goes on."
Seventh seed Henin-Hardenne ensured there was no repeat of her shock first round exit at Wimbledon with an impressive 6-3 6-0 win over Czech Zuzana Ondraskova.
Russian sixth seed Elena Dementieva, the runner-up last year, recovered from a slow start to quell another Czech, Lucie Safarova, 7-5 6-3.
Henman, the 12th seed, slumped to a dismal 6-4 6-2 6-2 defeat to Spain's Fernando Verdasco.
"If you're not healthy you can't compete at this level," the disappointed Briton said.
Rusedski, the 28th seed, was beaten in three sets by in-form American James Blake, the winner at New Haven on Sunday.
Murray bravely overcame Romanian Andrei Pavel 6-3 3-6 3-6 6-1 6-4, having vomited apparently from exhaustion early in the fifth set.
Pavel, ranked 83 places above the 18-year-old, was later penalised a point for swearing at the umpire following an over-rule.
Russian sixth seed Nikolay Davydenko beat Czech Tomas Zib 6-2 6-0 6-4.
Former French Open champion Gustavo Kuerten earned only his third tournament win of 2005 with a four-set victory over American Paul Goldstein, the Brazilian serving 35 aces in the process.
However, another ex-Roland Garros champion Juan Carlos Ferrero of Spain, seeded 20, lost 7-5 7-5 6-1 to Frenchman Arnaud Clement.
Argentine 11th seed David Nalbandian, the 2003 semi-finalist, came through in three sets against Alex Bogomolov of the US.