Olympic champion Chen Long of China suffered a surprise defeat to Thailand's Tanongsak Saensomboonsuk in the second round of the All England Open Badminton Championships here on Thursday.
The fifth-seeded Chen, who won the event in 2015, lost 21-6, 21-19 to the 27-year-old Thai, who recorded one of his biggest victories in his career.
It was Chen's second year in a row to crash out in the second round of the world's oldest badminton tournament. He was dumped by compatriot Xue Song last year.
Six-time winner Lin Dan reached the quarterfinals with a 21-11, 21-12 victory over fellow Chinese Huang Yuxiang while top seed Lee Chong Wei of Malaysia braved a left knee injury to beat Wang Tzuwei of Chinese Taipei 21-18, 21-18.
