We all know it by now: the Washington Football Team's defensive line, which features four first-rounders, is one of the most dominant groups in the NFL.

That isn't just a hyperbole, either; it's a flat-out statement of fact. It led a defense that was fourth in stuffed run percentage and tied for sixth in adjusted sack rate, according to Football Outsiders. The group accounted for 32.5 sacks, which more than 14 teams could muster from their entire defense in 2020.

So yeah, they're good. 

That was just the group's first year in Washington's new scheme, and as scary as it might be for offenses, there's still plenty of room to grow, said defensive line coach Sam Mills III. As players like Chase Young, Montez Sweat and others aim for new goals, more time in the system is only going to help them fine-tune their development.

"We gotta focus on the details," Mills said. "We've got a lot of things we can clean up, areas we can get better at. I think you have to keep in mind this is a young unit, so there's still a lot of growth left."

The first thing Mills stressed to his players is that any team, whether it's a championship-caliber squad like the Buccaneers or one that finished last year with one of the worst records, has to start "at the bottom of the mountain," as he put it. That doesn't necessarily mean forgetting what they accomplished last year, but he wants them to start from scratch so they can perfect everything about their skillset.

The benefit is that Washington's defensive line, while still young, already has a heavy load of snap counts over the years to rebuild upon. Jonathan Allen and Daron Payne have played at least 64% of the defensive snaps over the past three seasons. Sweat has started in every game of his career, and Young saw the third-most snaps among defensive linemen after Allen and Payne.

"They know partly what this journey is going to be about, because they've done it," Mills said. "They understand now, and it's very evident in OTAs."

That experience will help the defensive line get a good start on fixing areas that need improvement and continuing their development in others. A prime example of that is its performance against the run. There were some positives -- the defense finished tied for 10th in average yards allowed -- but there were serious lapses like 181 rushing yards from the Seahawks that resulted in the unit giving up an average of 113 yards on the ground.

There were flashes, however, that showed the potential for a better run-stopping group. The Steelers only amassed 21 rushing yards, while the Cowboys were limited to 60 on Thanksgiving. The Bengals finished with 70 in Week 11, but it took five rushers, including quarterbacks Joe Burrow and Ryan Finley, to reach that total.

While they're not entirely to blame for the inconsistent play, there are some things the defensive line could do to help improve those numbers. Mills saw the group improve against the run as the season went on, so he would like to see them build that progress at a quicker rate this year and get more comfortable with their assignments.

"We've got to start off right if we want it to be where we need it to be for this team to win, and part of that is just accountability and doing your job," Mills said. "Like Coach [Ron] Rivera said, we will play the run on the way to the quarterback. We will do that. We will continue to do that. But I think it's just experience in the room, experience in our system, that will help these guys out."

Mills also saw improvements in passing game from players like Young and Sweat, particularly in regards to the speed of their play. It allowed them to get more efficient rushes, he said, and that was obvious as they fill up the box score on a weekly basis. Eight of their combined 16.5 sacks came in the second half of the season, and they each scored their first-career touchdowns off an interceptions from Sweat and a recovered fumble from Young.

It was a good starting point for both players, but now Mills wants them to take their understanding of the game even further. Sweat is a little further ahead because he has one more season of experience under his belt, but he could see both of them start to get a firmer grasp of the game.

"You could really see Montez turn over quicker with that," Mills said. "You could see Chase from the very first game to the last game...really start to understand, 'Okay, this is what's going on. These are the looks I'm getting. This is how I'm gonna have to beat my opponent.' Both guys...are gonna have to continue to grow and master it."

And when it comes to improving that, time is the key ingredient to that.

"It's knowing pass sets. It's knowing formations. It's knowing, 'Okay I'm probably going to get a double team here, so maybe I'll work with my partner next to me,'" Mills said. "It's just time on task and being very familiar with situations that you're going to encounter."

Young, Montez and maybe even more experienced players like Allen and Payne encountered new schemes and looks last season. This year will be different, Mills said. They saw a lot of different looks, and they had to learn how to counter them on the fly. And as they reclimb the proverbial mountain that Mills mentioned, they'll be more familiar with the territory.

"They understand what we're trying to get accomplished," Mills said.