Indonesia and Malaysia launched a fierce Southeast Asian assault to trample on China's dreams of repeating their London sweep of all five Olympic badminton titles at the Rio Games on Monday.

Chan Peng Soon and Goh Liu Ying landed the first blow, dumping London silver medallists Xu Chen and Ma Jin in their mixed doubles semi-final with a 21-12 21-19 win to send Malaysian fans at the Riocentro into a frenzy.

Indonesia's Tontowi Ahmad and Liliyana Natsir then delivered the knock-out punch by upsetting the reigning champions Zhang Nan and Zhao Yunlei 21-16 21-15 in the other semi-final.

It was a bruising day for a nation which has dominated the sport at the Olympics like no other.

"I'm feeling really sad," 26-year-old Zhang told Reuters, pledging to return with the team at Tokyo in 2020.

"Since the last Games, I prepared so hard to defend the title and sacrificed a lot, but in the end I just didn't play as well as I had wanted."

The title will remain in Asian hands, however, with the gold medal decider set for Wednesday.

Typically, Asian players are well represented at the pointy end of the tournament, but the British flag was raised high over the Riocentro as rank outsiders Chris Langridge and Marcus Ellis stormed into the men's doubles semi-finals.

The world number 22 pair have had a dream run, stunning the third-ranked South Koreans in the pool round and on Monday they upset Japan's eighth-ranked Hiroyuki Endo and Kenichi Hayakawa 21-19 21-17.

"If you had said before we came here that we would be in the semis, I would have bitten your hand off," a thrilled Langridge told reporters.

The Britons will play China's formidable Fu Haifeng and Zhang Nan on Tuesday for a place in the final.

The Malaysian duo of Tan Wee Kiong and Goh V. Shem compete in the other semi-final against another Chinese pairing in Hong Wei and Chai Biao.

Londoner Rajiv Ouseph later made the last eight of the men's singles, edging Indonesia's Asian champion Tommy Sugiarto 21-13 14-21 21-16.

He faces fourth-ranked Dane Viktor Axelsen, who ended the fairytale run of Scott Evans, the Irish street-fighter who became his nation's first to win a match and make the last 16 at an Olympic badminton tournament.

The women's singles has gone with the seeds, but fourth-ranked Thai Ratchanok Intanon fell in the last 16 to feisty Japanese counter-puncher Akane Yamaguchi 21-19 21-16.

Spanish world champion Carolina Marin and London winner Li Xuerui headline the women's singles quarter-finals on Tuesday.