China's former world badminton champion Wang Yihan crashed out in the second round of the Japan Open on Thursday at the hands of Japanese giant killer Sayaka Takahashi.
Second-seeded Wang, the 2011 world champion and the runner-up to compatriot Li Xuerui at the 2012 London Olympics, bowed 21-13, 21-16 to Takahashi in 38 minutes.
Takahashi, currently ranked 12th in the world, beat world number-one Li 2-1 in the quarter-finals of the German Open last year.
"I went out feeling I had nothing to lose," said the 21-year-old Japanese, who also upset Thailand's 2013 world champion Ratchanok Intanon at the 2013 and 2014 Asian championships.
"I still cannot believe it because (Wang) is a player with such an awesome record."
Wang, 26, gave up an early lead to be caught by Takahashi at 8-8 in the first game. The world number-three lost six straight points after trailing 13-15.
In the second game, Takahashi led all the way from 5-all and broke away to victory by losing only one point after 16-15.
It was their only second-ever encounter; Wang took the first one 2-1 at the 2013 Hong Kong Open.
"I could not move aggressively today and allowed my opponent to control the game," said the Chinese player, who has won two events so far this year in the top-flight World Superseries this year -- in South Korea and Singapore.
Takahashi hurt her lower back when she lost a match in Japan's 3-1 defeat by China in the final of the Uber Cup women's team championship in New Delhi last month.
"Never mind the back pain. I do what I can do," she said, adding she was "determined" to win the Japan Open after failing to shine at the Uber Cup.
She has two victories to her credit, both in the second-tier Grand Prix Gold series. She won the Australia Open last year and the German Open in February.
Takahashi will play Taiwan's sixth-seed Tzu Ying Tai in the quarter-finals.
Top-seeded Li, who struggled in beating defending champion and 17-year-old Akane Yamaguchi in the first round, trounced compatriot Eriko Hirose 21-5, 21-16.
Big names among the men coasted to the quarter-finals with world number-one and top-seed Lee Chong Wei of Malaysia beating Germany's Marc Zwiebler 21-13, 28-26 in the second round.
China's second-seeded Chen Long, ranked second behind Lee in the world, whipped Hong Kong's Hu Yun 21-17, 21-15.
China's legendary Lin Dan, who has two Olympics, five world and five All-England titles under his belt, beat compatriot Gao Huan 21-17, 21-15 on his comeback this year after a seven-month sabbatical.