Duan Ying-Ying overcame a slow start to defeat Zarina Diyas in the first round of the Malaysian Open, but Elise Mertens fell to Lesley Kerkhove on a day frequently interrupted by rain.
Fifth seed Duan went 4-2 down in the opening set but rallied to secure a 7-5 6-3 victory over the Kazakh, converting the only two break points that came her way in the second set.
It was a different story for world number 69 Mertens, seeded seventh, as she was ousted 6-4 7-6 (7-4) by Kerkhove - ranked 126 places below her opponent.
Cagla Buyukakcay suffered the same fate after three sets against Risa Ozaki, while Nao Hibino fought off Maryna Zanevska to set up a second-round clash with either top seed Elina Svitolina or Jang Su-jeong.
There were also wins for Sara Sorribes Tormo, Zheng Saisai, Zhang Kai-Lin and Ashleigh Barty.