Top seed Caroline Wozniacki suffered an embarrassing first-round defeat against qualifier Wang Qiang at the BMW Malaysian Open in Kuala Lumpur today.
The Dane struggled for form in 2012 but there have been promising signs in the early part of this season and last week she reached the semi-finals of the high-class tournament in Dubai.
Wozniacki did not look in any trouble against China's Wang, ranked 186th in the world, in the early stages and led by a set and a break.
But after she missed a match point in the second set, Wozniacki was outplayed in the tie-break and 21-year-old Wang raced through the decider to win 2-6 7-6 (7/1) 6-1.
The rain that has dominated the first two days of the tournament largely stayed away today, but second seed Hsieh Su-wei will have to come back tomorrow to complete her first-round match against Kurumi Nara.
Third seed Anastasia Pavlyuchenkova had been held up by the rain yesterday but she eventually came through a tight tussle with fellow Russian Vera Dushevina 2-6 6-3 7-6 (8/6).
Fourth seed Ayumi Morita was an easy 6-1 6-1 winner over Cagla Buyukakcay, while there was a landmark 6-4 6-2 victory over Chanel Simmonds for 16-year-old former Wimbledon junior champion Ashleigh Barty - her first win on the WTA Tour.
Wang was not the only qualifier to prevail, with Zarina Diyas knocking out eighth seed Kristyna Pliskova, and there were also wins for Nudnida Luangnam, Luksika Kumhkhum and Akgul Amanmuradova.
Meanwhile, seventh seed Eleni Daniilidou survived a three-set tussle with Yuliya Beygelzimer, coming through 2-6 6-4 6-3, while Chinese pair Duan Ying-Ying and Zhang Shuai are also into round two.