Chinese pair Chen Yibing and He Kexin were deposed as Olympic champions on Monday as Brazilian Arthur Zanetti and Russian Aliya Mustafina accelerated the disintegration of gymnastics' world order.
Chen, a four-time world champion on the still rings, looked destined to retain his title from the 2008 Beijing Games until Zanetti pipped him to glory with the last routine of the men's rings final.
The women's uneven bars champion four years ago, He also made a strong start in her event final, only to see the gold medal adroitly prised from her grasp by a resurgent Mustafina.
Having claimed nine of the 14 golds on offer in Beijing, Chinese gymnasts have won only two to date in London.
Chen was the first gymnast to perform at the North Greenwich Arena on Monday and he finished his assured routine with a broad smile on his face.
His score of 15.800 points was not enough, however, as Zanetti edged him by just 0.100 points thanks to a higher execution mark, earning Brazil their first gymnastics gold in Olympic history.
"I hope this medal will open lots of doors for all the gymnasts in Brazil," said Zanetti, who will bid to defend his title at the Rio Games in 2016.
"I hope that in Rio we'll be able to have a full team, in order to defend this title and fight for others on home soil."
Italy's Matteo Morandi took the bronze medal behind 27-year-old Chen, who revealed his plans to retire after the London Games.
Bulgarian veteran Jordan Jovtchev, 39, also bade farewell to the Olympic arena, finishing in seventh place in the rings final on his record sixth Games appearance.
Mustafina made up for the disappointment of missing out on the individual all-around gold medal by claiming victory on the uneven bars, while Great Britain's Beth Tweddle took home a crowd-pleasing bronze.
Mustafina, 17, had already won individual bronze and team silver in London and she completed her medal collection thanks to a superb 16.133 display that left He with silver.
"I am very, very happy that I've won gold," said Mustafina.
"Every medal represents its own thing. I was hoping very much to win and I was very happy with my routine. I didn't know what to expect of myself today. I did my own thing."
It was Mustafina's first major title since she ruptured knee ligaments at last year's European Championships, and it gave Russia their first gymnastics gold medal of the London Olympics.
Tweddle bows out of the sport after finally adding an Olympic honour to her three world titles, her six European crowns, and her 2002 Commonwealth Games success.
"It was the one that was missing from my collection," said the 27-year-old, who finished fourth in the Olympic uneven bars final in Beijing.
"I wasn't bothered about what colour it was. I saw myself in third and I thought: 'Please don't be fourth again.' I just can't put into words what it means to me."
As China faltered, South Korea were able to celebrate a breakthrough success, after Yang Hak-Seon gave the country their first Olympic gymnastics gold in the men's vault.
The softly spoken 19-year-old averaged 16.533 points with his two vaults, putting him on top of the podium above Russia's Denis Ablyazin and Igor Radivilov of Ukraine.
"We haven't had a gold medal in Olympic gymnastics before and the training didn't go very well, so I was nervous," said Yang.
"But I'm happy that I got over that and won the gold medal."
The artistic gymnastics competition concludes on Tuesday with finals in the men's high bar and parallel bars and the women's floor exercise and balance beam.