Juliane Schenk, the women's singles defending champion at the Li-Ning Singapore Open, was upset 21-19, 21-15 by China's Yu Sun in the second round on Thursday.
Yu, one of the tallest badminton players in the draw at 1.83m, is ranked 74th in the world.
Said Schenk, the world No. 3 from Germany: "She was the better player today, so she deserved to win."
China's Wang Zhengming, a finalist in the men's singles last year, was also dumped out of the tournament after he went down Indonesian Tommy Sugiarto 16-21, 20-22.
But women's world No. 1 Li Xuerui spared the Chinese team's blushes when she rallied to beat Belaetrix Manuputi of Indonesia 21-19, 18-21, 21-14.
The hosts' campaign in the annual tournament ended after mixed doubles pair Terry Yeo and Yao Lei were defeated 21-15, 21-10 by Hong Kong's Lee Chun Hei and Chau Hoi Wah.