Spanish world number one Garbine Muguruza is out of the Wuhan Open in China after a quarter-final defeat by eighth seed Jelena Ostapenko.
Muguruza, 23, who needed treatment for a thigh injury before the final set, lost 1-6 6-3 6-2 to the Latvian.
French Open champion Ostapenko, 20, won the last six games to set up a semi-final with Australian Ashleigh Barty.
Barty, the world number 37, beat Czech third seed Karolina Pliskova 4-6 7-6 (7-3) 7-6 (7-2) earlier on Thursday.
Barty, who had previously not defeated a top-five player, failed to convert three match points in the third set but controlled the tie-break to seal victory over the former world number one.
Muguruza started the final set confidently following the medical timeout for a nagging left thigh injury, but Ostapenko proved too strong to clinch the match in just under two hours.
“I think she played very aggressively,” Muguruza said. “She had a lot of good shots, especially in the right moments.
“It was three sets and it was tight. I think she’s just playing very good with a lot of confidence.”
“In the first set I think I really wasn’t going for my shots,” said Ostapenko. “Then in the second and third sets I started to go for my shots, and change the directions more. I think it helped me pretty well.”
Greece’s Maria Sakkari, who beat Alize Cornet 7-6 (7-2) 7-5, and Caroline Garcia, who defeated Ekaterina Makarova 7-6 (7-3) 6-4 will contest the other semi-final.