Top seed Daniela Hantuchova battled past Taiwan's Chan Yung-Jan 7-6, 4-6, 6-2 to join Nadia Petrova and Patty Schnyder in the Bali Open semi-finals on Friday.
Slovakia's Hantuchova, last year's runner-up, negotiated an opening set littered with eight breaks of serve and saved two set points before taking the lead on a tie-break.
But Chan, a Strasbourg semi-finalist in May, levelled at a set each Hantuchova eventually steadied to claim victory in just over two-and-a-half hours.
Second seed Patty Schnyder had it much easier as she crushed Marta Domachowska 6-2, 6-2 in the 57th-ranked Pole's first quarterfinal of the season.
Earlier Russian fourth seed Petrova overcame a ragged start to beat Italy's Francesca Schiavone 6-4, 6-3.
Petrova recovered from 4-1 down in the first set, then raced away for her third consecutive straight-sets win against the fifth seed.
"I had a poor start and I got mad at myself," said Petrova, competing in Bali for the second time. "I didn't like the way I was playing."
Petrova will face Schnyder on Saturday trailing 5-6 in their series dating back to 2000.