INGLEWOOD (AP) — Josh Allen passed for 297 yards while accounting for four touchdowns, Von Miller had two of Buffalo’s seven sacks, and the Bills stamped themselves as a clear contender for the Rams’ Super Bowl crown with a 31-10 victory over Los Angeles on Thursday night.

Gabe Davis, Isaiah McKenzie and Stefon Diggs caught TD passes as the two-time defending AFC East champion Bills opened the NFL’s 103rd season by overcoming four turnovers and running away with a blowout win in the same stadium where the Rams won the Super Bowl nearly seven months ago.

Allen went 26 for 31 despite two interceptions. He also rushed for 56 yards, scrambling for a 4-yard TD when he stretched the ball over the line with 13:27 to play. The star quarterback took his share of hits, but he also dished them out and showed off a mean stiff-arm while Buffalo’s offense under new coordinator Ken Dorsey largely dominated the champs.

“There’s a lot to learn, but that second half, that’s who we want to be, going out there and executing that way,” Allen said. “We were 90% on third down. That’s a recipe for success.”

Matthew Stafford passed for 240 yards with one TD and three interceptions on a bruising night for the Rams, who lost a season opener and fell below .500 for the first time in coach Sean McVay’s six seasons in charge.

“Very humbling night, but one where you look yourself in the mirror and say you have to be better,” McVay said. “We weren’t ready to go. That’s on me. … There were a lot of decisions I made that didn’t put us in the best position to succeed. It was a very humbling night.”

The Bills’ seven sacks were the most allowed in McVay’s tenure with the Rams, who lost two starters from last year’s offensive line and attempted to replace them internally.

Diggs punctuated the domination with a 53-yard TD catch with 9:25 to play, talking trash to Rams All-Pro defensive back Jalen Ramsey afterward.

“We’re going to make the plane do backflips on the way home tonight,” Miller said. “We’re going to celebrate this win, because you have to, but then we’re going to go back to the lab. We’re not going to let this success put our guard down.”

Super Bowl MVP Cooper Kupp had 13 catches for 128 yards and a touchdown, but the Rams’ night went quickly downhill after they unveiled their championship banner in a pregame ceremony. Los Angeles could not keep up with Allen’s creative playmaking or the Bills’ pass rush, and its only major offseason addition on offense — receiver Allen Robinson — had one catch on two targets.

The Rams even got shut out in the second half, ending a streak of 89 consecutive halves with a point since November 2019.

Miller made an immediate impact in his debut for the Bills, who signed him away from the Rams after he won a ring in his half-season in LA. But he was just one part of a defense that yielded only 177 yards before Los Angeles’ final, meaningless drive.

Aaron Donald made his 99th career sack in the first half, but the seven-time All-Pro had just two tackles as the Rams became only the second defending champions in the last 10 years to lose the following season opener. Los Angeles trailed 17-10 after three quarters, but Buffalo ran away with two lengthy TD drives early in the fourth quarter.

With Dorsey taking over from Brian Daboll, the Bills went 9 for 10 on third downs and racked up 413 total yards, but three first-half turnovers kept it close early.

Allen set a career high to start a game by completing his first 10 passes, but linebacker Terrell Lewis’ interception stopped Buffalo’s second drive in Rams territory. Rookie James Cook fumbled away his first touch for Buffalo moments later, but Dane Jackson made an interception two snaps after that.

Los Angeles finally scored on its fourth drive when Kupp made an exceptional toe-tapping catch in the back of the end zone on a precise throw three minutes before halftime. The Rams got the ball back on Troy Hill’s interception, and Matt Gay hit a 57-yard field goal to pull the Rams even at the halftime gun.

50K

With a long third-down pass to Kupp on his opening drive, Stafford became the 12th quarterback in NFL history to pass for 50,000 career yards. He tied Drew Brees as the fastest to the mark, doing it in 183 games.

TO THE RAFTERS

Along with the banner to celebrate last February’s title, the Rams also hung a banner in the south rafters at SoFi Stadium honoring the 1999-2000 Super Bowl champions from the St. Louis era. The brief pregame ceremony included owner Stan Kroenke, retired left tackle Andrew Whitworth — and free agent Odell Beckham Jr., who held aloft the Lombardi Trophy.

INJURIES

Bills DL Ed Oliver injured his ankle in the first half and tried to play through it, but couldn’t do much. … Rams rookie RB Kyren Williams injured his ankle in the opening minutes. … The Rams played without WR Van Jefferson, who had knee surgery early in training camp after starting 21 games last season.

UP NEXT

Bills: Host Tennessee on Monday, Sept. 19.

Rams: Host Atlanta on Sunday, Sept. 18.