Delran's Carli Lloyd scored the Americans' only goals, and Hope Solo made a handful of spectacular stops, including one in the 83d minute, to save the game.
"I was hoping my game would come," Solo said.
This women's team has attracted a new generation of fans by playing high-level soccer in tense, entertaining games. On Thursday, the Americans played in front of the biggest crowd that any of them - aside from captain Christie Rampone, the lone player remaining from the 1999 World Cup team - had ever witnessed.
Unlike any of their previous Olympics Games on foreign soil, Thursday night's game was played in front of a full house. Wembley, the legendary home of England's national team, was packed. A crowd of 80,203 turned out, the largest crowd for a women's soccer game in Olympic history and the biggest crowd to ever see a women's game outside the United States.
The fans were treated to an exciting game between the two best teams in the world. Though the United States took a 2-0 lead early in the second half, thanks to two goals by Lloyd, victory never felt secure. Japan, which had come from behind in the World Cup final to tie the game and then win on penalty kicks, was resilient and determined.
And Japan had a great chance to tie it in the 83d minute when Rampone turned over the ball near the U.S. 18-yard box. But Solo kept the U.S. team ahead with a spectacular save, diving quickly to her left when Japan's Mana Iwabuchi left-footed a shot from 15 yards out on an angle.
"The thing about great athletes is they show up when they're needed," Abby Wambach said. "Superstars don't go unnoticed for long."
Lloyd said, "I was nervous, but we have Hope Solo. That's what she does."
Solo made waves early in the tournament when she lashed out at soccer icon and NBC commentator Brandi Chastain on Twitter. The controversy raged in the Olympic media center and online, but it didn't seem to cause friction within the team, which was isolated in satellite cities around Britain. And if voicing her opinion put any more pressure on Solo, she didn't show it Thursday.
"I think I tend to play well under pressure," Solo said.
Wambach, who missed the Beijing Olympics with a broken leg, said the team gained a new determination after the World Cup loss.
"Teams can go one way or another," she said. "Our team chose the right path. Not only because we're standing on the top podium, but because the way we treated each other and how we worked and sacrificed. We knew if we believed in each other that no matter what obstacles we had - and we've had them - we'd get through it together."
They earned another gold medal. And they earned the respect of this soccer-loving nation.
"We need to have these moments, these promoted moments when the light shines so bright on our sport that it's noticed by not only our fans but non-fans," Wambach said. "We want clubs around Europe to think, 'You know what, we had a lot of people at Old Trafford and at Wembley.' I hope some of the owners of these big clubs take notice and start putting money into women's programs."
After Thursday night's game, they just might.