Coco Gauff secured her first win over a top-ten player in 10 months by beating doubles partner Jessica Pegula 6-3, 6-3 in the quarter-finals of the Eastbourne International on Thursday.
The 19-year-old American won the last six games of the match from 3-0 down in the second set to snap a seven-match losing streak against top-10 opposition.
The world number seven will face another compatriot in the semi-finals of the grass court tournament -- 2014 champion Madison Keys, who posted a 6-4, 6-1 win over Petra Martic.
After an early exchange of breaks, Gauff pounced in the sixth game. A clever drop shot enabled her to move up 4-2 and she maintained her lead for the rest of the opening set.
World number four Pegula struck back at the start of the second set, taking advantage of a series of forehand errors from Gauff to break and then coming up with a fine lob of her own to hold for 3-0.
But Gauff turned the tide, coming up with a series of deftly executed volley winners to level the set, going on to wrap up her victory in style.
"I'm really happy with how I played. I obviously know Jess very well, she's one of the best players on the tour for a reason," Gauff told the BBC.
Ninth seed Daria Kasatkina reached the last four when second seed Caroline Garcia retired due to a right shoulder injury. Kasatkina was leading 6-2, 2-1 at the time.
In the men's tournament, Argentine fourth seed Francisco Cerundolo advanced to his first tour-level semi-final on grass with a 6-2, 6-3 win against Zhang Zhizhen.
American Mackenzie McDonald beat Mikael Ymer 6-4, 3-6, 6-3.
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