China's Qian Tianyi shocked world No. 5 Mima Ito of Japan through full sets, while reigning champion Chen Meng failed to reach the women's singles last 16 at the World Table Tennis (WTT) Singapore Smash here on Monday.
Qian, who is ranked 22nd in the world, saved two match points en route to a 12-10 win in the deciding set, reports news agency Xinhua.
"I kept my tenacity in the game. Whether I led or trailed, I just stayed composed," Qian explained.
Qian will take on French veteran Yuan Jianan, who eliminated another Chinese paddler Fan Siqi 3-1.
Another full-set match went the other way for Olympic champion Chen, who lost the deciding set 11-8 to Elizabeta Samara of Romania. China's Wang Yidi was also out of contention after falling 3-2 to Miu Hirano of Japan.
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Also on Monday, Zhang Rui dispatched Georgina Pota of Hungary 3-1, and Chen Xingtong eased past Jeon Ji-hee of South Korea in straight sets.
Top seed Fan Zhendong got past Tiago Apolonia of Portugal 3-0, leading other three Chinese paddlers into the men's singles last 16.
Lin Gaoyuan edged Jang Woo-jin of South Korea 3-2, Wang Chuqin sailed past Canada's Eugene Wang 3-0, and WTT Star Contender Goa winner Liang Jingkun continued his favourable form to eliminate Feng Yi-Hsin of Chinese Taipei 3-0.
Fan also paired with Wang Manyu to defeat Romanian duo Ovidiu Ionescu/Bernadette Szocs 3-2 to reach the mixed doubles quarterfinals. Top seed Wang Chuqin/Sun Yingsha also entered the last-eight after beating Lubomir Pistej/Barbora Balazova of Slovakia 3-0.