Week 4 presents a huge matchup for the Bills.

Act I in a two-part regular season series will begin on Sunday at 1 p.m. when the Bills take on the Miami Dolphins. Buffalo's defense is coming off a performance where it produced five takeaways and nine sacks while the Miami offense produced the NFL's first 70-point game since 1966.

Here are five storylines to watch for ahead of Sunday's divisional matchup.

1. A rivalry renewed

We all know the AFC East has gotten more and more competitive over the last few years thanks to efficient offenses and tough defenses – which the Bills and Dolphins have both. Last year, the matchups between the two teams did not disappoint as they split the regular season with the Dolphins defeating the Bills in Week 3 (21-19) and Buffalo beating Miami in Week 15 (32-29). The Bills got the best of the Dolphins in the playoffs with a 34-31 final score in the Wild Card round.

Those three games were decided by three points or less. With the way the two teams have started the season, Bills and Dolphins fans should expect much of the same for this year's first matchup, especially with Miami coming off a 50-point trouncing of the Broncos and Buffalo coming off a 37-3 victory over the Commanders.

The excitement and magnitude surrounding a matchup this early in the season takes many back to when the Bills-Dolphins rivalry was at its peak in the 90s. Buffalo had Marv Levy and Jim Kelly. Miami had Don Shula and Dan Marino. The two met for the first time in the postseason in 1991, right when the rivalry started to really heat up with competitiveness. To date, the two have played each other in the postseason five times with four of those games coming in the 90s.

Bills Wall of Famer Steve Tasker says he remembers the passion of the fans most when looking back at the rivalry.

"Jim Kelly, Thurman Thomas and Bruce Smith, we had too many good players," Tasker said reflecting on those seasons. "Don Shula would come up with Dan Marino and a bunch of guys, and they were hard to beat. He was a great coach. And those rivalries were always meaningful too because the Dolphins were trying to win the championship.

"They were trying to win the division like we were, and they were in a position to do it. A lot of times in the second meeting in the regular season between the division rivals, it was for the division. Or even more so, it was for home field. And so, they were games that mattered. Much like this game this week."

Between 1990 and 1999 the two teams played in 24 games, including playoffs. The Bills won 15 of those 24.

As for what Sunday's game means to national media, it's at the top of everyone's list because of the talent that will be on both sides of the ball.

"This is my No. 1 game of the week for so many reasons," NFL Network's Cynthia Frelund said. "And for football fans, it should be people's No.1 too because AFC East aside, these are two of the most intriguing games and intriguing teams in all of football, right? Both of these teams could easily be playing in Las Vegas. And this could be big because seeding matters."

2. Bills pass rush vs. Tua Tagovailoa

The Bills defensive line is coming off a huge performance against the Commanders where they registered 15 quarterback hits and had seven different defenders generate at least four pressures according to Next Gen Stats. It's a confidence-boosting performance that can be a big positive heading into a game against a QB who leads the NFL in several statistical categories.

Miami's Tua Tagovailoa gets the ball out faster than any other in the NFL with a 2.36 average time to throw. Due to his speed in getting the ball out, it's been tough for opponents pass rush to get to Tagovailoa with enough time to be disrupt him. The QB has only been sacked once and hit a league-low five times through three games.

That doesn't mean the Buffalo pass rush group can't put pressure on him. They'll just have to be effective in different ways. Right now, the Bills are tied for the second-most sacks in the NFL with 12 and have the fourth-most quarterback hits with 23.

So far this season, when Tagovailoa does feel the pressure his passer rating drops to 57.7 compared to a clean pocket when it's 137.7. Through three games, the Bills have the highest pressure rate in the NFL at 13.3% according to TruMedia.

When trying to generate that type of pressure on Sunday, NFL Network's Cynthia Frelund thinks it starts with the eye discipline of due to the level of pre-snap motion Miami uses to trick defenses.

"I think part of it is going to be not biting at the tricks that they do," Frelund said. "It's the things that happen in the beginning before the play starts, all the different ways they try to disguise what's going on and how they're going to be managing, is it a pass versus a run. They have to be patient and make Tua Tagovailoa play Bills ball. The reality is they have to slow it down and make them play Bills football, not the other way around."

Bills assistant head coach and defensive line coach Eric Washington also thinks it comes down to being disciplined.

"You have to do a great job of just being extremely disciplined, not forgetting what we're trying to present and being aware of how we need to adjust, maybe multiple times before the ball is snapped and the play is actually presented to us," Washington explained. "So, we have to be extremely disciplined."

3. Can the Bills defense run it back vs. the fastest offense in the NFL?

It wasn't just the Bills defensive line that had a standout performance in Week 3 because the whole defense deserves credit for the impact they had against the Commanders. They became the first team since 1985 to record nine sacks and four interceptions in a single game.

The group is second-best in the NFL allowing an average of 11.7 points per game and they're getting ready to play the team who leads the NFL with an average of 43.3 points per game thanks to players like wide receiver Tyreek Hill, wide receiver Jaylen Waddle and running back Raheem Mostert. Is it possible the Bills could take a few things from Week 3's game and use that against the NFL's fastest team?

Sean McDermott says the defense has continued to show signs of improvement to start the season because of the way they have prepared.

"It's the preparation players put themselves through and the coaches have done a phenomenal job of getting them prepared during the week," McDermott shared.

Of course, Sam Howell and Tua Tagovailoa are two different quarterbacks in two different offenses, but the fact that they posted the NFL's second-highest pressure rate in a game since 2016 means they have several things going right to start the season.

Miami doesn't just rank first in points per game, the team also leads the NFL in total yards per game (550.3), yards per play (8.4), rushing yards per game (188.3), passing yards per game (362), red zone efficiency (78.6), plays of at least 20 yards (20), score percentage per drive (58.3%), and the list goes on.

"They have unreal team speed on the on the offensive side," Sean McDermott said. "That's really where my focus has been the last hour or two. And it seems like they added to it this offseason, so very good skill. Tua is throwing the ball extremely well, and their schematics are almost revolutionary in what they do. Coach McDaniel is very, very creative and does a lot of things to get you out of position on defense."

4. Why offensive opportunities will be important against the Dolphins D?

While the Miami offense is getting plenty of attention heading into the week, the Bills offense has been heating up of late as well. The Bills sit right behind Miami in overall NFL rankings averaging 30.33 points per game (2nd in the NFL). While Miami's offense ranks first in several statistical categories, its defense ranks more middle of the pack to start the season.

Through three games the Dolphins are allowing an average of 23.7 points per game (21st) and 361.3 total yards per game (23rd). To start the season the Bills offense is averaging 383.3 total yards per game (7th), a 51.2% 3rd down conversion rate (1st), a 53.3% score percentage per drive (4th) and 35:45 average time of possession (3rd).

When it comes to scoring opportunities against Miami, offensive coordinator Ken Dorsey thinks they'll need to operate at a high level knowing the challenges that a Vic Fangio defense can create.

"I think they've obviously got a lot of talent on the defensive side of the ball up front and secondary wise, really that whole unit," Dorsey said of Miami's defense. "So I think right now they're playing extremely sound football. They're forcing the offenses to have to execute at a high level based off of what they're doing. They're creating problems for the quarterback with some of their disguises and the different things they do there.

"So it's a tough group that just really forces you to have to be on top of things to execute in both the run and pass game because they're physical, they play fast and they play sound in terms of what they're doing."

5. Allen's impressive home track record vs. Miami

QB Josh Allen has a great record against the Dolphins with eight wins in his 10 regular season games played against Miami so far in his career. When you look at that record on home turf, it gets even better. Allen is 5-0 against the Dolphins when the game is in Buffalo.

In those five games, Allen has totaled 17 touchdowns and posted a 112.7 passer rating. His offense has averaged 37.4 points per game, and he has averaged 240 passing yards per game in those contests.

Bills Mafia deserves a lot of credit for how they showed up and showed out at the Commanders game. So much so that Sean McDermott went out of his way to talk about it on Monday when meeting with the media.

"You guys need to celebrate the fans more," McDermott said with a big smile. "I mean that was incredible. I think it was louder when we were on defense than it was when they were on defense."

The team knows they'll need the help of their fans to show up and be loud for Sunday's big game.