NINE-TIME Thomas Cup champions and second seeds China were unceremoniously dethroned in New Delhi on Friday afternoon, after a 3-0 drubbing by Japan in the semi-finals in one of the biggest upsets in world badminton in decades.

World No. 4 Kenichi Tago gave the fourth seeds a flying start over the five-time defending champions by thrashing second-ranked Chen Long 21-13, 21-11 in 43 minutes.

Then world No. 3 pair Kenichi Hayakawa and Hiroyuki Endo kept up the pressure by edging out 15th-ranked Chai Biao and Hong Wei 22-20, 21-19 in 50 minutes.

China's sixth-ranked Du Pengyu took the first game against 19-year-old world No. 14 Kento Momota 25-23 on his second game point but capitulated subsequently 18-21, 14-21 in the 1hr 25min thriller.

Japan will play 13-time winners and top seeds Indonesia or Malaysia in Sunday's final.

China had an easier time in the Uber Cup, reaching Saturday's final against either hosts India or Japan after beating South Korea 3-0 in the final four.

Li Xuerui beat Sung Ji Hyun 21-11, 21-19, while Bao Yixin and Tang Jinhua hammered Jang Ye Na and Kim So Young 21-11, 21-12, before Wang Shixian overcame Bae Yeon Ju 21-13, 16-21, 21-10 for a straightforward victory.