Croatian Ana Konjuh overpowered German Julia Goerges 6-3 4-6 6-3 at the Auckland Classic on Friday to reach her second career WTA final.
The eighth seed will meet American Lauren Davis in the final after seventh-seeded Jelena Ostapenko retired trailing 4-1 in the third set due to illness.
The unseeded Goerges stunned former world number one Caroline Wozniacki in the quarter-finals but Konjuh ensured there was not another shock at the tournament in which top seed Serena Williams was upset by fellow American Madison Brengle.
Ostapenko took the first set against Davis 6-4 before the American levelled the match and the Latvian was unable to continue after falling behind in the decider.
"I woke up with a fever, with coughing and everything. I feel much worse today than yesterday," Ostapenko said.
(Reporting by Amlan Chakraborty in New Delhi; editing by Ed Osmond)