British number three Anne Keothavong beat top seed Mona Barthel to reach the Aegon GB Pro-Series Barnstaple final.
The 28-year-old Londoner, who won the tournament in 2008, claimed her 13th win in 16 matches with a 6-3 7-6 (8-6) victory over the German.
Keothavong will play Marta Domachowska in the final after the Pole beat Ekaterina Bychkova 7-6 (7-3) 2-6 6-3.
"Super pleased to win today and be through to the final here in Barnstaple," she wrote on Twitter.
Keothavong is enjoying a strong end to the year that has seen her come through qualifying to reach the main draws at WTA events in Austria and Luxembourg.
She will go into Saturday's final at 1200 BST ranked 109 places higher than Domachowska at 91 in the world, but having lost their only previous meeting over three sets on American hard courts last year, despite having twice held match point.
Keothavong is also through to the doubles final with Czech partner Eva Birnerova.
British number one Elena Baltacha is through to the semi-finals of the $100,000 (£62,000) ITF event in Poitiers, France after beating Poland's Magda Linette 6-3 6-3.
The Scottish world number 58 will next play French wildcard Irena Pavlovic for a place in the final.
"It was actually a lot tougher than the scoreline makes it look," Baltacha said. "She played like she had nothing to lose and she swung on everything and really played above herself for a lot of the match.
"I just had to keep working hard and expecting the winners to come and stay strong. Players like that can be very dangerous and I was a break down in the second set before fighting back.
"That makes it very satisfying and a good one to get through."