Buffalo Bills wide receiver Amari Cooper (18) runs with the ball during the second half against the Tennessee Titans on Sunday in Orchard Park. AP photo

ORCHARD PARK — There’s little doubt that adding Amari Cooper instantly made the Buffalo Bills better.

Cooper was limited to 19 snaps on Sunday, five days after being acquired from Cleveland. Still, he filled a major hole in Buffalo’s patchwork receiver group by attracting the Tennessee Titans’ attention and opening passing lanes for himself and others.

Buffalo won 34-10 and Cooper finished with four catches for 66 yards and a touchdown. The 30-year-old’s impact was evident in the Bills’ overall production. Keon Coleman’s 125 yards receiving were the most by a Buffalo rookie since Sammy Watkins had 127 in 2014. And Josh Allen threw for 323 yards after averaging 193 through his first six games.

Encouraging as that might be, routing a flawed opponent in October shouldn’t be the measuring stick for the AFC East leaders, who still have much to improve upon if they hope to make a deep playoff run in January.

Slow starts remain an issue. Buffalo rallied from a 10-0 deficit and got away with a first half in which the offense gained 90 yards and three first downs while going 0 for 5 on third down.

The Bills overcame a 17-3 deficit in their 34-28 season-opening win over Arizona. But that’s not a sustainable formula for success, as evidenced by losses at Baltimore and Houston in which Buffalo fell behind early.

Those two losses should prevent anyone from assuming the Bills (5-2) are one of the NFL’s top teams, even though they have a big lead in their weak division. Buffalo’s victories have come against teams with a combined record of 9-23.

This weekend, they face a winning opponent when they travel across the country to play NFC West-leading Seattle (4-3). Buffalo also has Indianapolis (4-3), Detroit (5-1), San Francisco (3-4) and playoff nemesis Kansas City (6-0) on the schedule.

This still stands as a retooling year for the Bills, who are leaning heavily on Allen to lead a team filled with young players and journeymen.

Allen has done his part, having yet to throw an interception.

And Buffalo’s rookies such as Coleman, running back Ray Davis and defensive tackle DeWayne Carter are showing their potential. Carter made a game-changing play on Sunday by stuffing Titans running back Tony Pollard for a 3-yard loss on fourth down to open the third quarter, leading to Cooper scoring the go-ahead touchdown six plays later.

But the Bills are dependent on Allen staying healthy, Cooper adding a new dimension to the offense, and Von Miller and linebacker Matt Milano returning. Miller is eligible to return next week after serving an NFL-issued four-game suspension. Milano could be back as early as December after being sidelined in August by a torn left biceps.

The challenges ahead were not lost on coach Sean McDermott following the win over Tennessee, when he closed his news conference by saying: “Stay humble. Get back to work, and do our job.”

WHAT’S WORKING

Halftime adjustments. After being limited to 65 yards passing in the first half, Allen threw for 258 in the second half, a personal high for the seventh-year starter in the final 30 minutes. The defense, meanwhile, limited Tennessee to 72 yards and five first downs in the second half.

WHAT NEEDS HELP

Third-down conversions. Buffalo went 3 of 10 on third down, marking the fifth time this season the offense has converted 33% or less of its opportunities. The Bills were held to 33% or less only five times from 2021-23.

STOCK UP

DE Greg Rousseau. The fifth-year player was in on five tackles, including a half-sack, and was credited with a season-best six quarterback hits.

STOCK DOWN

WR Mack Hollins. Cooper’s arrival is expected to put a dent into Hollins’ playing time.

INJURIES

LB Terrell Bernard did not return after hurting his right knee, and WR Curtis Samuel was sidelined in the first quarter with a shoulder injury.

KEY NUMBERS

23-2 — The Bills’ record against quarterbacks with 16 or fewer starts since 2019. Mason Rudolph took the loss on Sunday.

NEXT STEPS

A trip to Seattle, where the Bills have won two of their past three visits but are 3-6 overall.