A double to Carli Lloyd gave United States its third successive women's Olympic football title with a 2-1 win over Japan in the gold medal match at Wembley Stadium.
Two goals from midfielder Carli Lloyd, a header after eight minutes and a rasping shot from the edge of the box in the 54th, set the US on its way to a fourth Olympic gold from the five women's tournaments played.
Japan, which beat its rival on penalties in the World Cup final last year, halved the deficit after 63 minutes when the American side failed to clear its lines, and Yuki Ogimi scored from close range, her third goal in successive matches.
Japan dominated in attack from then on but could not find an equaliser and was denied what looked like a certain goal seven minutes from time when US goalkeeper Hope Solo made a world class save from substitute Mana Iwabuchi.
The attendance of 80,203 was a record for a women's match at an Olympic Games, beating the 76,481 at the Atlanta Games in 1996.
It was also the biggest crowd to watch a women's football match in Britain, beating the 70,584 that saw Britain play Brazil at Wembley earlier in the tournament.
United States rode its luck during the first half when Japan hit the bar twice and had what looked like a legitimate penalty appeal turned down.
After Lloyd gave the Americans an early lead, when she dived in to head the ball home just as Abby Wambach was shaping up to shoot, Ogimi should have equalised but was denied when Solo palmed her header on to the bar after 18 minutes.
Six minutes later US benefited from a dubious refereeing decision in the box.
A well-struck free-kick clearly hit Tobin Heath on the left arm but, instead of awarding Japan a penalty, German referee Bibiana Steinhaus waved play on.
US had also benefited from being given a penalty in their semi-final when the ball struck a Canada defender's arm as she was turning away and the referee ruled in the Americans' favour.
Its next piece of luck came in the 33rd minute when Shinobu Ohno rattled the bar with Solo well beaten.
Japan had its own slice of fortune before the break when Azusa Iwashimizu headed against the inside of her own post and saw the ball run across the face of goal before bouncing clear.
Japan, playing some neat passing moves, was never intimidated by the more expansive Americans and its perseverance paid off when Ogimi forced the ball home after Solo and her defence failed to clear.
London 2012 has given women's football in the UK an 'unprecedented platform' on which to create a lasting legacy, according to the Football Association's head of national game Kelly Simmons.