The United States, Russia and hosts Great Britain exploited sloppiness from Japan and defending Olympic champions China to set the pace in men's artistic gymnastics qualifying on Saturday.
Dominant in Beijing four years ago, China were completely out of sorts and finished the day with the sixth-highest qualifying score, while Japanese superstar Kohei Uchimura fell twice as his team wound up in fifth place.
The USA were the chief beneficiaries, registering a total score of 275.342 points that put them above Russia (272.595), with Britain (272.420) third.
It is the first time a British team have reached the men's gymnastic final since 1924.
The scores will be wiped clean when the teams cross swords again in Monday's all-around team final at London's North Greenwich Arena, when France and Ukraine will complete the line-up.
Guo Weiyang symbolised China's toils. A late replacement for the injured Teng Haibin, he fell off the pommel horse and produced a clumsy floor display, culminating in a face-first fall that contributed to a dismal score of 12.266.
"One of the gymnasts is a substitute, and he made quite a few mistakes due to a lack of experience," said Chen Yibing of team-mate Guo's display.
"We think that we should beat Britain, but because of the substitute and various other things, we didn't perform as we should have."
Three-time world champion Uchimura has been tipped to sweep all before him in London, but he came off the high bar and earned a score of just 12.466 on the pommel horse following a fall and an incomplete dismount.
He was awarded a mark of 15.766 on the floor, a 16.033 on the vault, and a 15.533 on the parallel bars, but finished the day in ninth place and will only compete in the floor and individual all-around finals.
"There were a couple of mistakes that happened at different stages, notably on the high bar, and that created a bit of uncertainty," said Uchimura of his team's performance.
On his own errors, he said: "I'll try not to make any more mistakes. We'll practice tomorrow (Sunday), so I'll try to improve."
Britain were solid throughout, and saw Kristian Thomas and Daniel Purvis make the early running in the individual scores.
Olympic bronze medallist Louis Smith delivered an impressive 15.800 routine on the pommel horse, prompting huge cheers from the home crowd that brought tears to the British star's eyes.
"I knew that if I got through my routine I'd break down, because it's been such an emotional four years," he said.
On the reaction of the supporters, he said: "It was magical, it really was. When they announced us and the crowd erupted, it blew your socks off."
American fans replaced their British counterparts in the afternoon session and they, too, had plenty to cheer about.
Jonathan Horton made up for falls on the pommel horse and the parallel bars with a fine 15.566 routine on the high bar, while 20-year-old Danell Leyva claimed first place in the individual all-around standings.
"I didn't see China's score, but I was aware that Japan was having a rough day," said US team captain Horton.
"I watch routines all the time and I see Kohei struggling and some other guys struggling, but I wasn't really focusing on that at all.
"We did a good job and managed to stay within our own little team container."
Germany impressed in the third and final qualifying session, but two-time world silver-medallist Philipp Boy hurt his ankle on the vault and fell on the high bar, denying him a place in the final of the individual all-around event.
Bulgaria's Jordan Jovtchev established an Olympic gymnastics record by appearing in his sixth Games at the age of 39, and he squeezed into the rings final in eighth place.