The Buffalo Bills suffered a gut-wrenching loss at the hands of the Pittsburgh Steelers, falling to 0-1 on the opening week of the 2021 NFL season. Buffalo entered the game as large favorites and despite some early offensive struggles, their first-half defense looked strong enough that a win was in sight. However, the offense sputtered and the defense fell apart as the game went on and ultimately, Pittsburgh came away with a win after outscoring the Bills 23-3 in the second half.

Here are the four biggest takeaways from Week 1.

No answer for T.J. Watt, Cameron Heyward

T.J. Watt signed a record-breaking contract in the days leading up to the game and on Sunday, he proved that he was worth every penny. Watt was utterly dominant, taking Bills’ right tackle Darryl Williams to the woodshed. Watt finished the game with two sacks and four quarterback hits. Both sacks were huge plays for the Steelers – the first resulted in a fumble that Pittsburgh recovered, and his second was on third down that subsequently led to touchdown on a blocked punt.

On the interior, Buffalo was outmatched by defensive tackle Cameron Heyward. Heyward was a force throughout the game. He reset the line of scrimmage in the run game and generated consistent pressure up the middle in the passing game, forcing Josh Allen to make off-balance throws. Heyward finished with four tackles, one sack, two pass breakups, one forced fumble and one fumble recovery.

Both guard positions are question marks for the Bills going forward, as neither Cody Ford nor Ike Boettger proved that they could handle a premier talent on the interior like Heyward as they rotated in and out throughout the game.

Run defense stout

One of the lone bright spots from Sunday’s contest was Buffalo’s run defense. Aside from a 25-yard gain by Chase Claypool on a reverse and an 18-yard rush by Najee Harris, Buffalo’s defense was strong against the run. Without Star Lotulelei in the lineup, Buffalo did a good job controlling the line of scrimmage for the majority of the game.

Harris, Pittsburgh’s first-round draft pick, finished the game with 45 rushing yards on 18 attempts. The Steelers’ offensive line was a weak point entering the game, so it was encouraging to see the Bills handle their business in that department.

Ed Oliver, in particular, stood out against the run. He regularly drove Pittsburgh’s linemen into the backfield off the snap, forcing runs outside, and while he didn’t fill up the stat sheet, he was a key contributor on defense throughout the game.

Josh Allen up-and-down

Since entering the NFL, Josh Allen has been one of the more overly-scrutinized players in the NFL. But after signing a massive $258 million extension during the offseason, his play will be picked apart even more. On Sunday, the critics were given some more ammo to critique his game.

Allen was constantly under duress, leading to a handful of errant throws. He completed 30-of-51 passes (58.8-percent) for 270 yards and one touchdown. He didn’t throw any interceptions, but he fumbled twice, losing one. He overthrew a handful of deep passes and the chunk plays just weren’t there.

The Steelers did a great job keeping things in front of them and limiting yards after the catch. Stefon Diggs caught nine of his 14 targets for just 69 yards, while Cole Beasley turned in only 60 receiving yards on eight receptions (13 targets). Gabriel Davis was the most impactful receiver, reeling in a 37-yard reception and a three-yard touchdown.

Buffalo’s offensive line did Allen no favors against a stout Steelers’ defensive front. Going forward, the Bills must clean up their pass protection if they hope to get the most out of their franchise quarterback.

Pass rush fizzles in second half

Buffalo’s revamped defensive line opened the game in a frenzy. Mario Addison and Jordan Poyer tallied first-half sacks, while the rest of the unit forced consistent pressure on Ben Roethlisberger. As a result, Roethlisberger completed just six-of-12 passes for 57 yards in the first half.

But the Steelers made adjustments at halftime and the Bills’ pass rush fizzled. For much of the second half, Roethlisberger got the ball out quickly, negating any effort by Buffalo’s defensive line. In the second half, Roethlisberger went 12-of-20 for 131 yards and one touchdown. While not huge numbers by any means, Roethlisberger was quick and efficient in the second half, and ultimately, Buffalo’s defense gave up too many chunk plays in the second half and couldn’t hang around any longer.