Unseeded Barbora Krejcikova of the Czech Republic reached her first Grand Slam semi-final at the French Open on Wednesday as she beat 17-year-old Coco Gauff 7-6 (8/6), 6-3.

The 33rd-ranked Krejcikova saved five set points in the opening set and finished off Gauff, the 24th seed, on her sixth match point to set up a clash with reigning champion Iga Swiatek or Maria Sakkari for a spot in the final.

Krejcikova, who is also through to the last four of the women's doubles with Katerina Siniakova, claimed her 10th successive win on the tour having arrived in Paris on the back of a maiden singles title in Strasbourg.

"I'm here and I'm in the semi-finals, and I never really imagined I'd be standing here one day on this court, especially in singles, and being able to win," said Krejcikova, a 2018 Roland Garros doubles champion.

"Already for me this is something I'd never dreamed of."

Krejcikova recovered from a rocky start, falling 3-0 and 5-3 behind against Gauff, the youngest Grand Slam quarter-finalist since 2006.

But the Czech saved a set point on the Gauff serve in the ninth game, and fought off two more at 5-6 to secure a vital hold and force a tie-break.

Two superb forehand winners snuffed out another two set points for Gauff, as Krejcikova won the last four points of the tie-break to clinch the first set after 70 minutes.

"I think it was very important. I was down all the time. I just had to go for every point and every ball and just enjoy it. I just made it somehow," said Krejcikova, battling nerves of her own after racing 5-0 ahead in the second set.

"In the second set I started really well and I was leading. I got a little bit tight."

Gauff saved five match points but eventually fell short, ending her run after becoming the youngest American woman to make the last eight in Paris since Jennifer Capriati in 1993.

"She's incredible," said Krejcikova, 25. "She's 17 years old. When I was 17 I played ITFs, I played 15Ks."

"I just told her to keep going, and her time's going to come."

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