Defending Swiss champion Roger Federer has lost to Robin Söderling of Sweden in a rainy French Open quarterfinal, 3-6, 6-3, 7-5, 6-4.
The loss on Tuesday ended Federer's record of reaching the semifinals in 23 consecutive major events.
The upset was the second pulled off by Söderling in as many years at Roland Garros.
He ended the reign of four-time champion Rafael Nadal of Spain in the fourth round a year ago, clearing the path for Federer to win his first French Open title.
Federer beat Söderling in last year's final. Before Tuesday, Federer was 12-0 in matches against the Swede.
As a result of Federer's defeat, Nadal will reclaim the number one ATP ranking next week if he wins the title. And the upset raises the possibility of a Nadal-Söderling rematch in the Paris final.
It will be a grand slam semifinal without Federer for the first time in six years.
Söderling's recent improvement was evident as he controlled rallies from the baseline. Federer found himself on the defensive and unable to move forward.
Söderling saved a set point in the third set when he won a frantic rally, then won the set to take the lead shortly after a rain delay of 75 minutes.
The upset was all the more surprising because Federer was in control early. He won 22 of his first 24 service points and led 30-love in his first service game of the second set when he suddenly faltered, losing four points in a row.
A backhand wide by Federer gave Söderling his first break, and he held serve the entire set to even the match. It was the first set Federer had dropped in the tournament.
Söderling made a narrow escape to extend the third set serving at 4-5. Trailing love-30, he hit a forehand that was called wide, but the umpire climbed off his chair, checked the mark and ruled the shot a winner.
Instead of love-40 and triple set point for Federer, the score was 15-30.
"I didn't think I played a bad match," Federer said. "He came up with some great tennis. It's much easier to digest this way."
On match point, the 1.93-metre Swede hit a second serve that Federer couldn't put in play. Söderling walked to the net with his fist up as if ready to continue the fight, then pumped it to punctuate the breakthrough against his nemesis.
"This is a big win, but it's not the final," Söderling said. "I don't want to celebrate too much. I want to focus on the next game."
His opponent on Friday will be No. 15 Tomas Berdych, a first-time grand slam semifinalist and the first player from the Czech Republic to reach the Roland Garros semifinals since 1992. There's the tantalising prospect that the final on Sunday will be a Nadal-Söderling rematch.
The men's semifinal round will be the first at a Grand Slam tournament without Federer since he lost in the third round of the 2004 French Open to Gustavo Kuerten. That's the last time he lost to anyone other than Nadal at Roland Garros.
Federer now begins preparations to bid for a seventh title at Wimbledon. "You move on to the grass and forget a little bit," he said. "I think I can move away from this rather fast."
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Match record: 688-162
Career singles titles: 62
Career singles titles: 7
Grand slam titles: 16 – Australian Open (2004, 2006, 2007, 2010), French Open (2009), Wimbledon (2003, 2004, 2005, 2006, 2007, 2009), US Open (2004, 2005, 2006, 2007, 2008)