Kurumi Nara's hopes of winning the Japan Women's Open on home soil came to an end when she was beaten in three sets by Jana Cepelova at the quarter-final stage on Friday.
Nara, attempting to add to the solitary WTA singles title she won in 2014, ousted third seed Yulia Putintseva to reach the last eight, but the 24-year-old then went down 3-6 6-4 6-1 to Slovakian Cepelova.
Putintseva was a break down in the second set after losing the first, but the unseeded world number 116 came storming back and broke six times to set up a semi-final against Christina McHale.
Seventh seed McHale, a beaten semi-finalist in Tokyo last year, saw off Viktorija Golubic 6-3 5-7 6-3 despite racking up seven double faults as the American was rewarded for saving 15 break points.
Zhang Shuai will take on Katerina Siniakova in the other semi-final after the sixth seed from China beat Varvara Lepchenko 6-7 (4-7) 6-1 6-3.
Siniakova only needed two sets to seal her semi-final berth, breezing past Alison Riske 6-2 6-4 in only 67 minutes.