Andy Murray produced a sizzling display from the baseline to hand world number one Roger Federer his first opening-round defeat since 2004 with a 6-7 6-3 6-4 victory at the Dubai Championships on Monday.
The 12-times grand slam champion was last beaten in the first round of a tournament at the Cincinnati Masters in August 2004.
"I definitely could have played much better tennis but then again you've got to give credit to the guy who beat you and came up with shots," said defending champion Federer, who has now lost two of his three meetings with the Briton.
With neither player facing a breakpoint in the first set, Murray was quick off the mark in ensuing tiebreak.
The 20-year-old charged into a 5-2 lead and held a set point at 6-5 but squandered it with a weak return.
Federer made the most of the reprieve and bagged the breaker 8-6 thanks to a forehand error from Murray.
The unseeded Murray capitalised on the only breakpoint in the second set by firing a forehand crosscourt winner to break Federer in the sixth game.
While Murray fought well for every ball on the baseline and served well throughout, unleashing 10 aces, the top seed made numerous forehand errors and looked the weaker player in the third set.
After fighting off two break points in the opening game, he was broken to love at 2-2, and Murray dropped just two points in his final three service games to earn a well-deserved victory.
"I've been really mentally weak for such a long time and not held up in pressure situations, and I showed tonight that was not going to be an issue," Murray, who has won two tournaments this year, told reporters after the one hour 54-minute match.
"I stayed calm the whole way through the match.
"In terms of my serving that was pretty special today. I've worked on my serve a lot and to beat Federer in a three-set match and not have a break point against you, I don't think that's happened to him for a long time."
Murray also credited his success to his mental strength.
"The most important thing is just to believe you can win the match," the 11th-ranked Murray said. "I think too many times on the tour some guys try to play almost too well, and it's really important to stay patient and not make rash decisions early in the match.
"I definitely didn't do that today."
Federer was playing just his second tournament of the year, and his first match since losing to eventual champion Novak Djokovic in the semi-finals of the Australian Open in January.
"Tough match, obviously. It was always going to be a tough draw," said Federer. He's played many matches already this season whereas obviously I come in a little bit cold.
"I knew it was important to get off to a good start but it wasn't enough tonight. He did well to hang in there and it was a tough match in the end.
"My expectations are not sky-high at this point. Obviously I haven't played much so you don't go in with any expectations. You hope to get past the first round, no matter if it's a guy with no ranking or a guy ranked basically in the top 10.
"I wish I would have maybe had a little bit easier draw, but under the circumstances I felt I played okay. It wasn't a bad match, which is the only positive thing out of tonight."
Fourth seeded Spaniard David Ferrer beat Germany's Tommy Haas 6-3 6-0, fifth seed Nikolay Davydenko of Russia defeated Kuwait's Mohammed Al Ghareeb 6-4 6-0.
Seventh-seeded Frenchman Richard Gasquet beat Russia's Dmitry Tursunov 6-4 6-4. (Reuters)
Murray hands Federer first round exit in Dubai