Updated

Reigning champion Su-Wei Hsieh won a pair of matches Thursday to secure a berth in the quarterfinals at the Malaysian Open hardcourt tennis event.

The second-seeded Hsieh opened her day by pasting Chinese Zhang Shuai 6-2, 6-2 in a first-round match that was suspended on Wednesday and capped it with a 6-7 (5-7), 6-3, 6-4 second-round victory over Japan's Kurumi Nara.

Taipei's Hsieh, who beat Croat Petra Martic in last year's Kuala Lumpur final, will meet American wild card Bethanie Mattek-Sands in Friday's quarters.

Two other seeds reached the round of eight, as No. 3 Russian Anastasia Pavlyuchenkova handled Uzbekistanian qualifier Akgul Amanmuradova 6-3, 6-3 and No. 4 Japanese Ayumi Morita topped Thai qualifier Nudnida Luangnam 6-3, 6-1.

A pair of seeds lost on Thursday, as Czech Karolina Pliskova bounced No. 5 Misaki Doi of Japan 6-4, 7-6 (9-7) and Thai qualifier Luksika Kumkhum upended No. 7 Greek Eleni Daniilidou 6-2, 6-4.

Meanwhile, Aussie Ashleigh Barty erased Kazakhstani qualifier Zarina Diyas 7-6 (7-3), 6-4, Austrian Patricia Mayr-Achleitner whipped Chinese qualifier Qiang Wang 6-3, 6-2 and Mattek-Sands straight-setted China's Duan Ying-Ying 6-1, 6-4.

Friday's other quarterfinals will pit Pavlyuchenkova against Barty, Morita versus Kumkhum and Mayr-Achleitner against Pliskova.