Nuremberg - Dutch title holder Kiki Bertens booked her ticket to Saturday's Nuremberg WTA final after semi-final opponent Misaki Doi of Japan retired.
Doi, 26, called time on Friday's semi-final as she trailed 2-6, 1-0 to her 25-year-old Dutch rival on the Bavarian clay.
Bertens, ranked 19, will meet Czech qualifier Barbora Krejcikova who ousted Romanian Sorana Cirstea 6-4, 4-6, 6-0, as she bids for a third WTA title and first since Nuremberg last year.
Meanwhile, Germany's Laura Siegemund, who was forced out of the tournament on Wednesday after a fall, confirmed she has ruptured a knee ligament and will miss next week's French Open.
"As some of you might have heard already, I injured my knee in a match at the WTA tournament in Nuremberg. The diagnosis is a rupture of the ACL," she wrote on her Facebook page on Friday.
The 29-year-old, ranked 32nd in the world, was injured in the last 16 and had to be carried off court after winning the first set against Krejcikova.
Siegemund, the 2016 US Open mixed doubles champion with Mate Pavic, had been in good form this season.