Mary Pierce rolled back the years to knock out top seed Lindsay Davenport in the quarter-finals of the French Open.
French player Pierce, who reached the final at Roland Garros 11 years ago and won the title in 2000, delighted the Parisian crowd with a 6-3 6-2 win.
In the last four, 30-year-old Pierce, seeded 21 this year, will play another Tour veteran, 29-year-old Elena Likhovtseva of Russia.
The 16th seed beat 15-year-old Sesil Karatancheva 2-6 6-4 6-4.
Davenport, who will stay top of the world rankings after Maria Sharapova also lost her quarter-final, had struggled throughout the tournament and been taken to three sets in all of the previous rounds.
And she seemed out-of-sorts against Pierce, with her serve in particular looking very vulnerable.
She showed some brief resistance, saving a match point and breaking Pierce when the French player served at 5-0 up in the second set.
But it was only delaying the inevitable as Pierce, who has reached just one WTA Tour quarter-final this year, finally won on her third match point after an hour and 19 minutes.
Play was briefly interrupted as Pierce first served for the match when a protester ran across the court the Philippe Chatrier court but the intruder was hastily removed by stewards.
Davenport admitted that she had not been at her best throughout the tournament.
"I beat my expectations (by reaching the quarter-finals) but at the moment I'm kind of down with the tennis that I played," said the 28-year-old American.
Pierce in contrast was amazed by what she called a "crazy" win.
"I have just beaten the world number one in straight sets," she said. "I need a bit of time to realise what I have done."
Karatantcheva had been attempting to become the youngest winner of a Grand Slam title in the modern era.
She began well, breaking the nervous Likhovtseva twice in the first three games and took the first set 6-2.
But the next two sets saw the players trade service breaks as neither seemed able to establish a lead.
In the end, it was the much more experienced Likhovtseva, who is nearly twice as old as her opponent, who came through.
"She played really well but I don't think I really believed I could do it," said Karatantcheva, who defeated Venus Williams in the third round.