Alison Riske advanced to the Shenzhen Open final for the second straight year by beating Camila Giorgi 6-3 6-3 in the semi-finals.
There she will play Katerina Siniakova, who earlier shocked Britain's Johanna Konta with a 1-6 6-4 6-4 win.
Such a result barely seemed possible after Konta breezed to the first set in just 22 minutes, dropping only 13 points.
But Siniakova, the Czech No.4, beat Simona Halep earlier in the tournament and reproduced the goods with a range of power serving and baseline hitting.
A solitary break in the second set was enough to level it up, but her plight looked perilous in the decider as Konta had one foot in her third WTA final, leading 4-2.
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But the 20-year-old reeled off four successive games, including a love-service hold, to clinch her first final on the tour.
Riske, earlier avenged her loss to Agnieszka Radwanska in last year's final by beating the top-seeded Pole in Thursday's quarter-finals.
