American wild card Bethanie Mattek-Sands upset defending champion Su-Wei Hsieh to reach the semifinals at the Malaysian Open hardcourt tennis event.
The 27-year-old Minnesota native Mattek-Sands knocked out the second-seeded Hsieh 7-5, 6-2 in Friday's quarterfinal action.
The Taiwanese Hsieh beat Croat Petra Martic in last year's Kuala Lumpur finale.
Mattek-Sands semifinal opponent on Saturday will be third-seeded Russian Anastasia Pavlyuchenkova, who blew past young Aussie Ashleigh Barty 6-2, 6-0 on Day 5.
The other semi will pit fourth-seeded Japanese Ayumi Morita against Czech Karolina Pliskova. Morita came from behind to beat Thai qualifier Luksika Kumkhum 6-7 (7-9), 6-4, 6-1, while Pliskova vanquished Austrian Patricia Mayr- Achleitner 7-5, 6-1.
The 2013 Kuala Lumpur champion will collect $40,000.