Little-known Elizaveta Kulichkova knocked seventh-seed Bojana Jovanovski out in the first round of the WTA Malaysian Open on Monday.
Kulichkova, a Russian ranked 171 in the world, beat the Serbian in straight sets 6-3, 6-3.
Sixth-seeded Kurumi Nara of Japan also made it to the next stage, beating Switzerland's Stefanie Voegele 6-3, 7-6, in hot and humid conditions in Kuala Lumpur.
Nara started the match strongly but the determined Swiss mounted a challenge in the second set.
"Voegele played really well today, especially in the second set as she put up a really tough fight and refused to let up," said Nara.
"But I managed to subdue her with some good serves and some really positive thinking of winning the match, which helped me prevail."
Ukraine's Kateryna Kozlova won as well, 6-3, 6-4, over China's Saisai Zheng.
Top seed Caroline Wozniacki will meet China's Wang Yafan on Tuesday.
The Danish star is looking to atone for a brief outing last year in Malaysia when she lost in the first round.
Source: AFP