Tries from Kotaro Matsushima, Yoshikazu Fujita and Amanaki Mafi, as well as 13 points from Ayumu Goromaru secured the win as Japan were forced to hold off a resilient USA side, who crossed over with scores from Takudzwa Ngwenya and Chris Wyles.
Japan settle for third spot in Pool B, and become the first side to win three games and exit the tournament at this stage, while USA head home with four defeats to their name.
Read below to find out how the drama unfolded.
Rugby World Cup (@rugbyworldcup) October 11, 2015
"So after three weeks of much entertainment and excitement, the 2015 Rugby World Cup's pool phase comes to a close in Gloucester this evening. While there may be little riding on the game in terms of the final positions of these two sides, both will be desperate to end on a positive.
Japan in particular will be keen to make it three wins from four, with the next instalment of this competition due to be held in their Far East homeland."
USA: Chris Wyles (capt); Takudzwa Ngwenya, Seamus Kelly, Thretton Palamo, Zach Test, AJ MacGinty, Mike Petri; Eric Fry, Zach Fenoglio, Titi Lamositele, Hayden Smith, Greg Peterson, Al McFarland, Andrew Durutalo, Samu Manoa.
Replacements: Phil Thiel, Oli Kilifi, Chris Baumann, Cam Dolan, John Quill, Danny Barrett, Niku Kruger, Folau Niua
JAPAN: Ayumu Goromaru; Yoshikazu Fujita, Harumichi Tatekawa, Craig Wing, Kotaro Matsushima, Kosei Ono, Fumiaki Tanaka; Keita Inagaki, Shota Horie, Hiroshi Yamashita, Luke Thompson, Justin Ives, Michael Leitch (capt), Michael Broadhurst, Ryu Koliniasi Holani.
Replacements: Takeshi Kizu, Masataka Mikami, Kensuke Hatakeyama, Shinya Makabe, Amanaki Lelei Mafi, Hendrik Tui, Atsushi Hiwasa, Karne Hesketh
"We could witness some history this evening at the Kingsholm, too, as Japan may become the first side to ever win three fixtures in the pool phase but still exit the competition. They have won many admirers both in the UK and back home, and they are backed by a fantastic army of supporters once more this evening."
"It had been a positive enough start to the contest from the US, but how about that reply from Japan? The attack epitomises exactly what the Brave Blossoms are all about, recycling possession and getting themselves over the line. Brilliant rugby."
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"A decent enough opening 40 minutes of rugby, then, which threatened to truly burst into life without actually doing so. Plenty to look forward to in the second half as both sides inevitably look to go out with a bang. Japan are on the brink of becoming the first side to win three of their pool fixtures but still crash out - bittersweet indeed!"
"The United States seemingly struggling for ideas at the moment and failing to truly ask questions of their opponents. This is a good spell, though, and one that they really need to be making the most of if they are to pick up their first point."
"Things have turned massively in Japan's favour over the past 10 minutes or so, which gives the impression that this one is as good as over. But this is now a chance for the Brave Blossoms to showcase their talents once more on this world stage over the concluding minutes. They will be a big loss to this tournament."
For USA, it's a fourth successive Pool B campaign. The big feeling will be disappointment, but there have been flashes which suggest that there is more to come from this side in the future.