The Bills' 35-31 victory - after having trailed 21-0 in sub-freezing conditions - ended high-flying New England's 10-game winning streak and kept the AFC East division title race alive.
"What makes this team this team - we're not out of it, we're going to continue to fight one play at a time, no matter what the score is," said Allen.
Reigning NFL Most Valuable Player Allen orchestrated five consecutive drives with touchdowns, at least temporarily thwarting the Patriots' bid to reclaim the division title from Buffalo for the first time in five years.
The result underlined Buffalo's status as a strong Super Bowl favorite despite inconsistent form this season.
"Obviously, the last five-ish years, we've found sustained success, but never been able to punch our ticket to the Super Bowl," said Allen.
"And the end of the goal, that's every team's dream."
The Patriots had been utterly dominant in the first quarter, with quarterback Drake Maye rushing for two touchdowns in the snow and rookie TreVeyon Henderson running 52 yards for a touchdown and a 21-0 lead.
The Bills battled back. Allen found James Cook and Dawson Knox with touchdown passes on either side of halftime.
Cook then barely kept the ball airborne as he stretched across the line for a third Buffalo touchdown that officials initially ruled out, before Allen seized the lead with a powerful 14-yard sling to Knox.
Henderson briefly reclaimed the advantage for New England with a stunning 65-yard sprint for a touchdown. But Cook barged through the Patriots' line for the game-winning touchdown score.
New England - who dominated the NFL in the Tom Brady era of the 2000s and 2010s - still have three more regular season games to claim the AFC East, which they lead over the Bills by a single game.
Chiefs out, Ravens and Jaguars dominate
The Kansas City Chiefs - the most dominant team in the NFL over the past decade - saw their slim hopes of making the playoffs officially end.
The Chiefs' 16-13 loss to the Los Angeles Chargers, combined with other results, means Patrick Mahomes and his team will miss the playoffs for the first time since 2014.
Kansas City have won three Super Bowls from five appearances since 2020, but saw a sharp drop off in form this season. To compound their misery, quarterback Mahomes limped off the field Sunday with a left knee injury that was later diagnosed as a torn ACL, ending his 2025 season.
Coach Andy Reid said the knock "doesn't look good" and will require medical scans.
"The guys are down. They busted their butt to win the game and I wouldn't expect anything less... it's not a great feeling," he added.
Elsewhere, the Baltimore Ravens ended Cincinnati's slim playoff hopes with a dominant 24-0 win, their defense shutting out Bengals star quarterback Joe Burrow.
Quarterback Lamar Jackson completed eight of just 12 passes for 150 yards, two touchdowns, and one interception. Baltimore put up 189 rushing yards, led by Derrick Henry's 100 yards on 11 carries led all backs, while defensive end Kyle Van Noy and safety Alohi Gilman had 'Play of the Game' in the early slate of games.
And Jacksonville quarterback Trevor Lawrence managed six total touchdowns (five passing) as the Jaguars demolished the New York Jets 48-20.
Running back Travis Etienne Jr. had three of those five touchdowns from Lawrence, also leading all receivers in the game with 73 yards, including 51 on the ground with a fourth total touchdown.
Jacksonville finished the game with 428 total yards and forced three turnovers as they own the No. 3 seed in the AFC.
Rivers returns, Rams down Lions, Broncos extend win streak
After being up for Hall of Fame selection this year, the 44-year-old Philip Rivers un-retired to start at quarterback for the Colts on Sunday, almost leading them to a win over the Seahawks in Seattle.
Rivers finished the game with 120 passing yards, one touchdown, and one interception on 18-of-27 passing as the Colts lost 18-16.
Colts kicker Blake Grupe drilled a 60-yarder with 47 seconds left in the game to give Indy a 16-15 lead. He would finish the game going 3-for-3 in field goals, accounting for nine of the Colts' 16 points.
But the Seahawks drove down the field and got kicker Jason Meyers within 56 yards. He took advantage of the opportunity and drilled a 57-yarder to give the Seahawks the 18-16 lead with 18 seconds left in the game.
Seattle would hand the Colts their fourth-straight loss, and fifth in the last six, while they improved to 11-3 on the season.
The Rams defeated the Lions 41-31 despite having trailed 24-14.
Detroit collapsed as this season's MVP front-runner quarterback, Matthew Stafford, ran the Rams' show with two passing touchdowns.
The victory was marred by a hamstring injury to star wide receiver Davante Adams, whose status is in the air for next week's Thursday night game as he deals with a hamstring injury.
Adams was optimistic about being able to play in the game, but head coach Sean McVay said it "doesn't look good" for his chances of playing.
In Denver, moments after Green Bay Packers star linebacker Micah Parsons limped off the field with yet another nasty-looking injury, which is being reported as an ACL tear, the Broncos pulled ahead with a rushing touchdown from rookie running back RJ Harvey, his 10th on the season.
Denver has now won 11 straight games and are in sole possession of the No. 1 seed in the AFC.
