Bethanie Mattek-Sands sent second seed Su Weh Hsieh crashing out in the quarter-finals of the Malaysian Open.
The American's 7-5 6-2 triumph means no defending champion or top seed has ever won the event, now in it's third year.
"It's a new feeling for me because it's the first time I'm defending a title," said Hsieh. "I tried my best to retain the title and hold on to my ranking points."
Mattek-Sands will now meet world number 29 and third seed Anastasia Pavlyuchenkova, who brushed aside Australian youngster Ashleigh Barty 6-2, 6-0 in just an hour.
Japan's Ayumi Morita edged closer to winning her first ever WTA title after beating Luksika Kumkhum of Thailand 6-7 7-9 6-4 6-1.
Karolina Pliskova of the Czech Republic eliminated Austrian Patricia Mayr-Achleitner 7-5, 6-1 to set-up the meeting with Morita.