Russian fourth seed Ekaterina Makarova will face unseeded Czech Karolina Pliskova in the final of the Pattaya Open after both claimed three-set victories on Saturday.
Makarova, whose only previous title came when she won Eastbourne in 2010, edged past Czech Andrea Hlavackova 6-3, 0-6, 6-4.
While Pliskova, who will also be chasing her second career title after winning in Kuala Lumpur in February 2013, beat Germany's Julia Goerges 6-3, 4-6, 6-3.
Makarova struggled to gain the upper hand, despite breaking to lead 2-0. She had to fight off a break point before securing the first set, and then failed to win a game in the second as her more aggressive opponent put her on the defensive.
But the final set mirrored the first, with Makarova taking an early break to lead 2-1 when her return forced an error, and with her again having to save a break point before closing out the match.
After failing to win any of three match points on her opponent's serve at 5-3, Makarova finally claimed victory with her fourth.
"The best part of my game is that I was fighting," said Makarova. "She's playing so aggressive, so flat. It was difficult to return because she was serving so good today.
"At the end of the second set I was so angry because here I'd already played two matches in three sets and I really wanted to finish it in two sets. But she played amazing all that set and it was difficult to do anything."
Pliskova played a solid match and was the steadier player throughout. Although Goerges served the first two of her 16 aces of the match in the opening game, she dropped her serve with a forehand error.
The Czech broke serve again to lead 5-2 but double-faulted on set point and then was broken when Goerges struck a stinging forehand winner.
But Goerges then surrendered her serve and the set with two consecutive double-faults.
In a contest that consisted almost entirely of very short points, neither player earned a break point in the second set until Goerges took advantage of a weak game by her opponent to break for 5-4, then serving out at love.
In the final set it was Pliskova's steadier game that gave her the edge. She broke serve to lead 2-0 and, although Goerges recovered the break with a spectacular forehand winner down the line in the fifth game, Pliskova immediately responded with a further break to lead 4-2.
Goerges then faced two match points at 5-2, and although she survived that threat Pliskova was able to serve out the match to love.
"There weren't any rallies because we were both serving well and we have similar games, so it was tough," said Pliskova, who fired 13 aces of her own.
"In the second set she was serving really well. I almost couldn't do anything. I tried to stay calm and play my game and wait for my chance."