Alison Riske gained revenge for her Shenzhen Open final defeat to Agnieszka Radwanska last year by beating the world number three to reach the last four on Thursday.
Top seed Radwanska was far too strong in a showdown at the tournament in China 12 months ago, but the American prevailed 6-2 3-6 6-0 on this occasion.
Defending champion Radwanska lost the opening five games in the first match between the two since the 2016 final and was broken on seven occasions in a surprise loss.
The 39th-ranked Riske was unable to rally from 4-0 down in the second as a resurgent Radwanska set up a deciding set, but the eighth seed lost only six points to bagel the Pole and book a semi-final against Camila Giorgi - a straight-sets victor against Wang Qiang.
Riske said: "The ultimate goal is to go one better than last year, but I can only look to the next match and I feel if I keep focusing on myself, my game, then who knows what can happen."
Johanna Konta takes over as the favourite to win the title after the third seed saw off the challenge of Kristyna Pliskova to win 6-4 3-7 (11-13) 6-3.
The powerful Pliskova served 15 aces and gave Konta a stern test, but the world number 10 had the edge in a contest which lasted two hours and 12 minutes, earning the solitary break in the final set after losing a marathon tie-break in the second.
Brit Konta will now come up against the unseeded Katerina Siniakova, who followed up her shock success against Simona Halep by dumping Nina Stojanovic out in straight sets.