Qualifier Zarina Diyas stunned eighth seed Kristyna Pliskova in three sets to reach the second round of the BMW Malaysian Open on Wednesday.
Pliskova of the Czech Republic is the second seed to fall, joining sixth seed Donna Vekic of Croatia, who lost in the opening round on Tuesday.
Third seed Anastasia Pavlyuchenkova of Russia also came close to crashing out but managed to keep her nerves to edge out compatriot Vera Dushevina 2-6, 6-3, 7-6 (8-6) in the rain-interrupted match.
"It is never easy to play a delayed match. I was ready to finish the match yesterday but the weather was not kind enough," said Pavlyuchenkova about the game, which started on Tuesday before heavy rain forced the players to stop.
"To play under these conditions is a big test and I am happy that I pulled through."
"I kept calm after losing my serve at a vital point, and my aggressive approach helped me a lot as she (Dushevina) was looking uncomfortable," said Pavlyuchenkova, who will meet Uzbekistan's Akgul Amanmuradova next.
Amanmuradova only completed her qualifying match against Ana Savic of Croatia early Wednesday to win 4-6, 6-4, 7-6 (13-11). The match was tied at 6-6 in the third when play was stopped late Tuesday due to rain.
After a short rest Wednesday, Amanmuradova returned to the court and defeated Taiwan's Kai-Chen Chang of 6-1, 6-3.
Meanwhile, fourth seed Ayumi Morita of Japan outclassed Turkey's Cagla Buyukakcay 6-1, 6-1.