The defending French Open champion and world number three was shocked by unseeded 17-year-old Amanda Anisimova in the quarter-finals at Roland Garros.
Teenager Amanda Anisimova breathtakingly took down defending French Open champion Simona Halep 6-2 6-4 to become the youngest grand slam semi-finalist in 13 years.
The unseeded 17-year-old took the match to Halep, mixing clean groundstrokes with phenomenal drop shots to set up a last-four meeting with Ashleigh Barty.
In the process, she became the youngest player to reach the last four of a major since Nicole Vaidisova's run to the semis at Roland Garros in 2006.
Defeating world number three Halep represented the biggest triumph of the American's fledgling career, with this only her fourth main-draw appearance at a slam. Anisimova only claimed her first WTA Tour title in Bogotá in April despite heading into that tournament without a prior match win on clay at that level.
For Halep, it ended her hopes of joining an elite group of five women – Margaret Court, Chris Evert, Steffi Graf, Monica Seles and Justine Henin – to retain La Coupe Suzanne-Lenglen.
Anisimova started the match by halting Halep's run of 16 successive breaks of serve – a streak that stretched back to her round-two win over Magda Linette – and a subsequent hold to love suggested the youngster would not cower on Court Philippe-Chatrier.
Anisimova grew in confidence and punished the third seed by angling a forehand slice into the open court for her 11th winner, which sealed the first set in fine fashion.
The teenager continued to excel off the ground and produced a searing forehand down the line for a break point in game two of the second set that was duly converted.
Anisimova showed her resilience to pass through a service game with a trio of winners as she shut the door on Halep's three chances to finally win behind her return, but she was unable to stop the Romanian hitting back at the next opportunity.
Errors started to creep in for Anisimova and after a chance to put herself in position to serve out the match arrived, she buried a forehand into the net as Halep drew level at 4-4.
However, the 2018 champion missed a chance to break and, in the next game, double faulted to give Anisimova match point, the American wrapping things up with a sweet backhand to retain her record of not dropping a set in Paris this year.
Amanda Anisimova bt Simona Halep  6-2 6-4
Halep - 16/17
Anisimova - 25/24
Halep - 1/2
Anisimova - 1/0
BREAK POINTS WON
Halep - 1/7
Anisimova - 4/7
FIRST SERVE PERCENTAGE
Halep - 72
Anisimova - 73
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Halep - 52/53
Anisimova - 64/64
Halep - 52
Anisimova - 68