The New England Patriots went 84 days without losing a football game. And that streak seemed destined to continue when they raced out to a 21-point lead over the Buffalo Bills at Gillette Stadium on Sunday.

Josh Allen had other plans, however.

The reigning NFL MVP helped the Bills rack up 28 points in the second half, as Buffalo staged a furious comeback to hand the Patriots a stunning 35-31 loss.

So, what went wrong in New England’s defeat, and who were the bright spots for a New England club that scored 30-plus points for the sixth time this season?

Our Patriots insider Phil Perry highlighted both the good and the bad from Sunday’s defeat in his “Stock Watch” report for Week 15:

Stock Up

TreVeyon Henderson, running back

Henderson is an explosive play waiting to happen. He changed the game with 52- and 65-yard touchdown runs, the second of which required great vision and a willingness to work off-script. But he also seems to be seeing openings and accelerating through them at the line of scrimmage on a more consistent basis. — Perry

Mack Hollins, wide receiver

Hollins had just four grabs for 41 yards, but he led the team with eight targets, and he could be in line for more busy days ahead. The Bills seemed to find some success by bringing pressure, spying Maye, and using physicality at the line of scrimmage with Maye’s eligible receivers.

The Patriots aren’t loaded with man-to-man beaters, but if teams try to replicate Buffalo’s plan, Hollins’ size could make him the kind of target that Maye trusts, even if he’s tightly covered. — Perry

Stock Down

Drake Maye, quarterback

Maye was remarkable with his legs, single-handedly helping the Patriots improve what had been a sketchy red-zone attack of late. And his block to help secure Henderson’s long score was selflessness in motion. But as a passer he looked tentative at times, and as his -2.1 percent CPOE (completion percentage over expected) would suggest, he was less accurate than we’ve come to expect him to be.

Was that weather-related? Was that simply Buffalo confounding him with morphing post-snap defensive looks? Either way, it was a down day for Maye through the air. — Perry

Brenden Schooler, special teamer

It could truly be the entirety of the Patriots kickoff coverage unit listed here since Ray Davis averaged a whopping 41.0 return yards on Sunday (four returns for 162 yards). But Schooler’s facemask penalty helped put the Bills on New England’s 42-yard line for one of their five consecutive touchdown-scoring drives.

Not what you’re looking for from the kicking-game captain. — Perry

Defensive front seven

James Cook averaged 4.9 yards per carry. The Patriots didn’t record a sack in the second half after picking up two in the first 30 minutes. There were openings up front against the run and undisciplined pass-rush reps that allowed the indefatigable Josh Allen to create with both his arms and his legs.

This unit could use a healthy Milton Williams and a healthy Robert Spillane. — Perry