The Michael Phelps-driven US team removed all argument about who was the top Olympic nation in London, leading both the gold medal table and the overall medal count ahead of China.
Quarrels raged in Beijing four years ago when the host nation won by far the greatest number of gold medals - 51 to America's 36 - but the US won more medals overall - 110 to China's 100.
No such distinction had to be drawn in London. The Americans won by any measure, spearheaded by a Phelps swansong which ended the most decorated career in Olympic history with four more golds, taking his personal tally to 18 gold and 22 in all, both all-time records.
The US headed into Sunday's final day of limited competition with 44 golds to China's 38, and 102 medals to 87.
Outgoing IOC President Jacques Rogge declined to involve the world body in establishing a universally accepted method of gauging national team performances.
"This is a game for the media," he told reporters ahead of the closing ceremony.
"You have to find a solution that is agreeable to everyone."
Rogge also declined to say whether London's Olympics were the best Games ever, as his predecessor Juan Antonio Samaranch had famously done at Sydney in 2000.
He said it was unfair to compare Games, though he described London's as "absolutely fabulous" and said he was "very happy and very grateful" to the 2012 organising committee headed by former athletics great Sebastian Coe.
Coe himself described it as an "extraordinary fortnight".
Rogge said his highlights included the record-breaking feats of Phelps and Usain Bolt, the Jamaican sprinter who recorded an unprecedented double by defending both his 100m and 200m crowns, and made it a "double treble" by helping Jamaica to back-to-back relay titles.
Rogge, often seen as a dry bureaucrat, also nominated a sentimental favourite - the emotional reaction of cycling great Sir Chris Hoy after his sixth gold medal set a new British Olympic record.
"The tears of Chris Hoy were the defining moment of the Games," said Rogge.
Bolt's final appearance in London in the relay also delivered what he had denied fans with his previous two victories - a world record.
The crowds packing the main stadium on Saturday night erupted in wild cheers as Bolt took the baton from Yohan Blake and ran across the finish line to help Jamaica to victory in a record 36.84 seconds.
That made him the first person to win golds in the 100m, 200m and the 100m relay at consecutive Olympic Games. But while he won all three with world-record times in Beijing, his victories in the two individual sprints in London were outside the world marks he set in 2009.
Bolt's victory followed one of the crowning moments for a deliriously happy and successful host nation when Mo Farah added a second gold to his collection by winning the 5000m.
The Somali-born runner, who a week earlier won the 10,000m, delighted the public by kissing the ground then doing a few situps.
Moments later, Caster Semenya from South Africa managed a silver in her Olympic debut in the 800m three years after being forced to undergo gender tests.
Mexico won its first gold of the games when Oribe Peralta scored after just 29 seconds and then added another in the second half to help his side beat Brazil 2-1, the country's first Olympic football title.