Japan had won 15 straight matches at the Tokyo Games but that streak came to a halt on Tuesday with losses in both men's and women's doubles, leaving badminton superpower China as the only nation yet to taste defeat.
Japan's Takeshi Kamura and Keigo Sonoda were overwhelmed by towering Chinese duo Li Jun Hui and Liu Yu Chen, who both stand about 6-feet-2 and rained down well-angled smashes to win 21-14, 21-16 in just 38 minutes.
"It was the hardest game for us in the group phase so far," said Liu, who dropped to his knees and let out a roar when he scored the winning point.
China has long been the dominant force at the Games, winning 41 medals since badminton became an Olympic sport in 1992 -- more than double the combined tally of Indonesia and South Korea, the second and third most successful countries.
Japan suffered another setback in women's doubles when world No. 1 pair Yuki Fukushima and Sayaka Hirota, whose injured knee was heavily bound, lost 24-22, 13-21, 21-8 to Indonesia's Greysia Polii and Apriyani Rahayu.
In another upset, the world No. 1 men's doubles team of Kevin Sanjaya Sukamuljo and Marcus Fernaldi Gideon from Indonesia lost to third-ranked Taiwanese duo Lee Yang and Wang Chi-Lin 21-18, 15-21, 21-17.
"They played very well because they really need to win this match to pass the group stage," Gideon said. "Their style is fast and they didn't make mistakes."
The Chinese women's doubles team of Chen Qing Chen and Jia Yi Fan defeated South Korean pair Kim So-Yeong and Kong Hee-Yong.