LONDON — They were on top of the world on Saturday, looking down at the Chinese far below. On Monday night, the US men’s gymnasts were sitting in their folding chairs looking as if the London Bridge had fallen down upon them. So it goes at Olympus when the medals are on the line.

China rebounded fiercely to win its third gold medal in four Games by more than 4 points over Japan, which needed a jury’s revision after their athletes left the floor to claim the silver after originally placing fourth.

“It’s a young team,” said US captain Jonathan Horton after the Americans had finished fifth in the team final, two places behind the exuberant British, who earned their first team medal since 1912, when their 23-man team competed in Stockholm in white knickerbockers and the Italian champions sported black stockinette pantaloons. “They’re trying to go out there and win a gold medal and that really built up.”

No US squad had finished first at a non-boycotted Games since 1904, when no foreigners competed in St. Louis. But after the Yanks won the qualifying round with a score (275.342) that would have been good for silver in the final, they couldn’t be blamed for fantasizing a bit.

“Can we just get the medals now?” Horton had joked.

Once they were actually up for grabs, though, the world turned upside-down on the Americans, who missed the podium for the first time since they finished fifth in Sydney in 2000. “You had a lot of teams out there that had a good day — and we didn’t,” remarked USA Gymnastics president Steve Penny.

Things went south from the opening rotation when Sam Mikulak stumbled at the end of his floor routine and Jake Dalton finished his with a giant step. That put the Yanks in fifth place and they never recovered, slipping as far as last place. The killer came on the next rotation when Team USA was unhorsed on the pommel, historically its weakest event. Danell Leyva came off the apparatus and John Orozco broke his rhythm and ended up sitting on the horse.

With their two top all-arounders messing up, their mates, now in seventh, were rattled. “I told them, “It’s the team final, three-up, three-count,’ ” said Horton, the only Beijing veteran in the bunch. “Anything can happen. We need to pull through this. It’s not over until it’s over.”

But when Orozco splattered his vault landing, the Americans were all but finished. With two rotations to go they were stuck in sixth, 4 points out of the medals. To their credit, they hung in and finished strong, placing third on both parallel bars and high bar and pulled ahead of the Russians, who missed the award stand for the third Games in a row.

“I’m super proud of them,” said coach Kevin Mazeika. “They had some struggles, but they never gave up and fought to the end.”

Still, it was a comedown for the Americans, who’d collected silver in Athens, bronze in Beijing, and missed a silver at last year’s world meet in Tokyo by .01 points behind the Japanese.

“It’s a tough day,” acknowledged Penny. “They had their sights set a lot higher.”

Nobody was going to catch the Chinese, who started slowly on rings but then finished first on vault, parallel bars, and high bar to put the rest of the planet behind them.

The only question was who would join them on the podium. The British, who’d qualified a team for the first time since 1992, had been in the mix all night as the crowd inside North Greenwich Arena, which included Princes William and Harry, urged them on, roaring at the end of each performance.

“To get a bronze medal is a miracle,” proclaimed Louis Smith, whose colleagues originally had earned the silver. “Silver, bronze, it doesn’t matter.”

In a trice, the hosts went from fourth behind Ukraine after the penultimate rotation to second when they left the floor to third after the jury, at Japan’s request, reviewed world champion Kohei Uchimura’s difficulty level on horse and awarded him an extra .7 points for his dismount. That decision left the Ukrainians, who thought they had the bronze, empty-handed.

“I feel sorry for them,” confessed Uchimura. “I shouldn’t, but I do.”

Post-facto podium shakeups aren’t how it happens in most sports but in this one, it’s never over until after it’s over.

“When you are in athletics, 100 meters is 100 meters,” mused Ukrainian coach Yuliy Kuksenkov. “Sometimes in gymnastics, is 95 or 105.”