Serena Williams felt she was her own worst enemy as she lost an epic three-setter to Svetlana Kuznetsova.
The loss in the French Open quarter-finals on Wednesday dashed her hopes of landing a second Roland Garros title.
Williams, the second seed, will have to wait another year to repeat her title-winning exploits of 2002 after being downed 7-6 (7/3) 5-7 7-5 by seventh seed Kuznetsova on Suzanne Lenglen court.
The American recovered from going a set down to take a 3-1 lead in the decider, but was eventually sunk when Kuznetsova clinched victory on the third of her match points.
While the Russian can look forward to a semi-final against 30th seed Sam Stosur tomorrow, Williams was left to reflect on what might have been, putting the blame for her defeat firmly at her own door.
"In the third set, I had an opportunity and I got really tight. And I pretty much gave it to her," said the 27-year-old.
"It was like I said, 'Here, do you want to go to the semis? Because I don't'. And she was like, 'Okay'.
"I made it hard for myself more than anything. Honestly, I think I lost because of me and not because of anything she did. I don't think that makes it easier."
Williams added it was the first time she had "got tight" since the Australian Open in 2007, a year she went on to win the title at Melbourne Park.
Williams played a poor tie-break to gift Kuznetsova the opening set.
The Russian went 5-3 up in the second but her opponent, a 10-time grand-slam winner, bounced back to win four games on the spin and take the match to a decider.
Kuznetsova finished the stronger of the two as Williams hung on grimly, saving two match points in game 10.
In her next service game, however, she skewed a backhand wide on the first of two more match points for Kuznetsova, 23.
It is the second successive year Kuznetsova has made the semi-finals here, and she was also a runner-up at Roland Garros in 2006 when she lost to Justine Henin.
"It was a very tough match," she said. "I'm very proud that I pushed myself and fought for the third set.
"She's a great champion. I respect her. Neither of us played great today but we both fought hard. I was lucky."
Kuznetsova is the second Russian to make the semi-finals, along with compatriot Dinara Safina, the top seed and title favourite.
She is the only player to defeat Safina on clay this year.
That makes her strong favourite to see off Stosur, the Australian who will be making her first appearance in a grand-slam semi-final.
The 25-year-old is a doubles specialist but she is making a breakthrough campaign in singles, clinching her spot in the last four with a solid 6-1 6-3 win over Romanian teenager Sorana Cirstea, the world number 41.
Stosur broke Cirstea five times in total as the 19-year-old, who had stunned fifth seed Jelena Jankovic in round four, struggled in blustery conditions on Philippe Chatrier court.
"I'm over the moon, happy, excited - every single positive emotion possible," said Stosur, who owns 22 tour titles in doubles.
"The last few years I've had a lot of doubles success, which is great. But this year, I definitely made a conscious effort to make singles a priority and I'm starting to see good rewards for those decisions."
Stosur's previous best display at a Major was a fourth-round appearance at the 2006 Australian Open.
She was struck down with viral meningitis and Lyme disease in the second half of the 2007 season, hospitalising her in Florida, and only made her return in April 2008.