Out-of-sorts Sabalenka knocked out by Andreeva, 17

Russian teenager Mirra Andreeva claimed the biggest win of her career against an out-of-sorts Aryna Sabalenka to reach the semi-finals of the French Open.

Second seed Sabalenka was seen grimacing and pointing to her stomach as she talked to medical staff in the middle of the first set.

She continued to struggle and appeared to consider retiring from the match.

Despite being far from her best, Sabalenka managed to move past her discomfort to complete the match.

But it was Andreeva who emerged victorious, wrapping up a 6-7 (5-7) 6-4 6-4 win.

The 17-year-old is the youngest Grand Slam semi-finalist since Martina Hingis at the US Open in 1997.

She will face Jasmine Paolini in the last four after the Italian stunned fourth seed Elena Rybakina earlier on Wednesday.

"Honestly I was really nervous before the match, I knew she'd have an advantage," said Andreeva, who had lost both her previous meetings with Sabalenka in straight sets.

"Me and my coach, we had a plan today but again I didn't remember anything. I just try to play as I feel."

After exchanging breaks early in the opening set, it quickly became apparent that Sabalenka was feeling under the weather.

The Australian Open winner became increasingly frustrated with her under-par performance and called for the trainer as Andreeva broke to go 4-3 up.

After talking to the match doctor and returning to the court, Sabalenka made a swiping gesture at her neck and seemed close to signalling her retirement.

But she appeared to brighten and managed to level the set at 5-5 before digging deep in the tie-break to take the opener.

The same problems returned for Sabalenka, and she often needed to crouch down and steady herself on her racquet, receiving a time violation on one occasion.

The 26-year-old looked close to tears for much of the second set and she made a slow, lethargic walk to her seat when Andreeva broke at 5-4 to force a decider.

Both players struggled to hold serve as the match trundled past the two-hour mark, and Sabalenka continued to receive medical attention.

World number 38 Andreeva capitalised on her opponents' struggles, deciding to strike at the crucial moment, landing an outrageous lob on her second match point at 5-4 to seal a famous victory.