Kristina Mladenovic came from a set down to upset top seed Belinda Bencic and earn a place in the Rosmalen Grass Court Championships final.
Third seed Mladenovic appeared to have a sizeable task on her hands after world number eight Bencic eased to the first set, but fought back brilliantly to win 2-6 6-3 6-4.
Mladenovic, who won the women's doubles title at the French Open with Caroline Garcia, dropped serve in the third game of the match before wasting four break-back points at 3-1 down.
She was punished for that profligacy as Bencic - who did not play at Roland Garros because of a back injury - earned a double break and claimed the opening set in commanding fashion.
Both players continued to look shaky on serve in the second, but this time it was Mladenovic who took advantage to force a decider, where she avenged last year's quarter-final loss at the same tournament to set up a final with Coco Vandeweghe.
Vandeweghe's route through to the final was more straightforward, seeing off American compatriot Madison Brengle in straight sets.
Sixth seed Vandeweghe needed just an hour and 11 minutes to seal victory 6-4 6-2.
Vandeweghe won 81 per cent of first serve points and never allowed Brengle to find a way through her defences, saving all four break points she faced.
Asked about the prospect of facing Vandeweghe, Mladenovic said: "Coco is such a great player, a tough one on grass. I'm just very happy to be through to the final, I hope I can play some good tennis."