Aryna Sabalenka's hopes of a first French Open title evaporated at the quarter-final stage as she collapsed to a 3-6 7-5 6-0 defeat against Diana Shnaider.
Sabalenka was the clear favourite to clinch the Roland-Garros crown following early exits for reigning champion Coco Gauff, four-time champion Iga Swiatek and world number two Elena Rybakina.
And she was only two points from victory on her own serve in the second set, only to be caught cold by a stunning fightback from Shnaider.
Sabalenka had been tested on serve in the opening set, but a pair of back-to-back breaks got her ahead, and she then surged into a 4-1 advantage in the second.
But a double fault at the worst possible moment gifted Shnaider one break back, and the 25th seed ran with her newfound momentum.
After failing to convert three break points in Sabalenka's next service game, the Russian found herself 6-3 5-4 down, but a booming forehand winner to the corner saw her get back on serve.
Sabalenka then showed clear signs of frustration, remonstrating with her box and firing off more unforced errors as Shnaider broke again to force a decider, helped by a lovely drop shot.
The world number one was far from her usual standards in the third set, as she was on the receiving end of a bagel for the first time since February 2024, versus Donna Vekic in Dubai.
Sabalenka produced 17 unforced errors in the third set alone, compared to just four from Shnaider, who will now face qualifier Maja Chwalinska - ensuring there will be at least one first-time grand slam finalist on Saturday.
"Honestly I am speechless," Shnaider said afterwards. "She is the world number one, so I was just trying to do my best. I had to fight for every point. "
LET’S GO #RolandGarros pic.twitter.com/GtZ7v2b2QC
— Roland-Garros (@rolandgarros) June 3, 2026
Sensational Shnaider causes biggest Roland-Garros shock yet?
Plenty of big names have underperformed at Roland-Garros this year, with both Jannik Sinner and Novak Djokovic suffering early exits in the men's singles draw, to go with those shock defeats for Gauff, Swiatek and Rybakina.
But this result - particularly given the manner of the third set - may just be the most surprising of all.
Shnaider is only the fourth player since the WTA Rankings were first published in 1975 to win a grand slam third set 6-0 against the world number one.
And she is in good company, as the only previous players to accomplish that feat are Steffi Graf (Roland-Garros 1995), Serena Williams (Australian Open 2005) and Maria Sharapova (US Open 2006).
It means this is the first grand slam since the 1977 French Open where both the men's and women's singles semi-finals will not feature a single former major champion.
Sabalenka was bidding to become the first woman to make the semi-finals at seven consecutive grand slams since Williams enjoyed a run of 10 in a row, between the 2014 US Open and the 2017 Australian Open.
Instead, there will be an intriguing clash between two left-handers for a final spot, in Shnaider and Chwalinska. This is the first grand slam to see two left-handed women reach the semi-finals since Wimbledon in 2014 (Petra Kvitova and Lucie Safarova).
