Japan beat three-time former champions the United States 48-41 in Paris on Monday to claim its first gold medal in Paralympic wheelchair rugby.
Katsuya Hashimoto scored 19 tries for Japan, which had secured bronze in the past two Games.
The Japanese had also beaten the U.S. in the group stages on Friday at the Champs de Mars Arena, in the shadow of the Eiffel Tower.
"We thought that if we could play our rugby well, we would win the gold medal," Japan's Hidefumi Wakayama told reporters.
"I'm already filled with all kinds of emotions, and I feel really happy," he added.
Defeat means the U.S. remains without a gold medal in the event, nicknamed "murder ball," since 2008.
"I feel so bad for our team," the U.S.' Chuck Aoki told reporters.
"Everyone worked so hard to get to this level and we were close, but it just wasn't enough," he added.
Earlier, world champions Australia claimed bronze by edging defending gold medalists Britain 50-48 in Paris.
Two-time former winners Australia lost out on the chance to fight for gold after losing to Japan in the semifinal on Sunday.
In a tight contest with the British, the Australians claimed victory to go one better than their fourth-place finish in Tokyo three years ago.
"It was nice to win convincingly in the final minute," Australia captain Chris Bond said. "We missed out on the gold medal match, which I think we were good enough to be in.
"We used that pain to fuel us today."
Britain had started its title defense with victory over Australia in its opening group match on Thursday.
"In the end there were too many errors in the game," Britain's Gavin Walker said.
"We go into another rebuilding process, another four years ahead of us and looking toward LA now."
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