ORCHARD PARK, N.Y. — For Bills fans, there are playoff victories — rare as they might be — and then there are playoff victories over the Patriots, the first of which happened on Saturday when Buffalo trounced New England, 47-17.

To say that this game, and this outcome, were long-awaited would be an understatement. No team has given the Bills more grief in the last 20 years than the Patriots, a team that won the A.F.C. East 16 times during that span. That run of success overlapped with a big chunk of the Bills’ 17-year playoff drought that ended in 2017.

Heading into Saturday’s game, the Patriots had a 77-46-1 franchise record against the Bills, a .626 winning percentage.

The departure of Tom Brady to Tampa Bay and the arrival of Josh Allen in Buffalo have reset the scales a bit: The Bills have won three of their four regular games against the Patriots the past two seasons.

But on Saturday, Allen’s near-perfect performance showed that the Bills are no longer tiptoeing past the A.F.C. East's longtime boogeyman. Like the Boston Red Sox finally beating the Yankees in 2004, Buffalo smote their longtime nemesis in epic fashion.

The Bills scored touchdowns on all seven of their offensive possessions. They did not punt the ball. They did not attempt to kick any field goals. They did not turn the ball over. On a freezing Saturday night at home, the Bills were nearly perfect against the Patriots, who have toyed with the team mercilessly for years.

“It’s big for this community,” said safety Micah Hyde, who had one interception and nearly scored on a 52-yard punt return in the fourth quarter. “We know the history for the last 20 years.”

From the opening drive, Allen sprayed passes to his fleet-footed receivers and ran past defenders. By halftime, the Bills had built a 24-point lead, the largest deficit in Patriots postseason history. For the game, Allen completed 21 of 25 passes for 308 yards and five scores. He ran 66 yards.

Last season, the Bills swept the Patriots, who were without Brady for the first time in two decades, and established a longer postseason as their target. A loss to Kansas City in the A.F.C. championship game evolved the team, under Josh Allen, from happy-to-be-here playoff entrants to title contenders even if that planned path ran through New England.

The Patriots surprised many observers this season by clawing their way back to the playoffs behind rookie quarterback Mac Jones, who played on an accelerated learning curve.

But after a seven-game winning streak, the Patriots went 2-3 down the stretch and entered the postseason as a wild-card team for the first time Patriots coach Bill Belichick’s tenure in New England. Despite giving up the second fewest points in the league, their defensive secondary was undermanned.

On Saturday, in the second coldest Bills home game ever — 7 degrees at kick off — Jones forced passes under pressure. Receivers dropped catchable balls. Jones was picked off twice and sacked three times by a Bills defense that had given up the fewest points in the league during the regular season. When he finally hit receiver Kendrick Bourne for the Patriots’ first touchdown late in the third quarter, narrowing their deficit to 33-10, the game was largely over.

Before kickoff, Jim Kelly and Thurman Thomas, cornerstones of the Bills’ four consecutive Super Bowl appearances in the early 1990s, were on the field to rile up the crowd that, based on years of experience, feared the worst but hoped for the best. Fittingly, Kelly, a Hall of Fame quarterback, wore a Josh Allen jersey while Thomas wore a Devin Singletary jersey to honor the Bills’ current running back who, like Allen, showed off his versatility on Saturday.

Singletary had 81 yards rushing, two scores in the second quarter, and three catches for 13 yards. His proficiency catching and rushing forced the Patriots to keep him under watch, helping Bills’ receivers Emmanuel Sanders, Isaiah McKenzie and Stefon Diggs to break free.

Allen seemed in control throughout, even when he wasn’t. On his first touchdown pass, he evaded defenders before lofting the ball to the back of the end zone as he fell out of bounds. Allen was trying to throw the ball away, but instead, tight end Dawson Knox hauled it in for an eight-yard score.

“I didn’t mean for that to happen,” Allen said sheepishly after the game.

Allen held the ball for 9.64 seconds on the play, the longest time for any touchdown pass in more than three seasons, according to the N.F.L.’s Next Gen statistics.

It was one of many plays Allen made on Saturday that cemented his reputation as a fan favorite. He toyed with the Patriots like few quarterbacks have, throwing and running at will. With the game out of reach, Allen tossed his fifth and final touchdown pass to offensive tackle Tommy Doyle, who lined up as an eligible receiver.

“The Bills just blew up the Death Star,” said Nellie Drew, a lifelong Bills fan from Buffalo, referring to the Star Wars space station. “Josh Allen is the young Jedi who has finally vanquished the eBill emperor,” Belichick.

Allen was playing in the fifth playoff game of his career, three of which came during the Covid-19 attendance restrictions of the 2020 season. The Bills won two home playoff games last January against the Indianapolis Colts and Baltimore Ravens, but both games were played in front of only a few thousand fans.

Saturday’s game, a near sell out with fans standing and stomping the entire game, felt more like the coming out party for a team on the rise. During the Belichick-Brady era, no team in the A.F.C. East had so talented a quarterback and so stifling defense.

The Bills will now play the lowest remaining seed in the A.F.C. after tomorrow’s Kansas City-Pittsburgh Steelers game. If Kansas City wins, the Bills will travel there for a rematch of last season’s A.F.C. conference championship, which the Chiefs won, 38-24.

And Buffalo is able to exact revenge, the Bills’ balance may come to define a new era.