The crowd was too loud at Fed­Ex Field, and rookie nose tackle Chris Neilddidn’t hear linebacker London Fletcher change the defensive call. When the ball was snapped, Neild ran right into the man next to him, Adam Carriker, and by happenstance ended up dragging New York quarterback Eli Manning to the ground for his first career sack.

“Luckily it turned out good,” Neild said, “because if it didn’t, I know that I would’ve been walking back with my head hanging, because I would’ve gotten chewed out.”

It was the kind of break the Washington Redskins didn’t often get in their first season running a 3-4 defense. But upgrades along the defensive line have already shown some quick returns.

A season ago, the Redskins generated no sacks from the nose tackle position. The entire defensive line had only nine through 16 games, most in nickel formations. One game into the season, they’ve shown considerably better numbers, and players say it’s not due to any change in strategy.

Defensive linemen were credited with all four of the Redskins’ sacks in last Sunday’s season-opening win against the Giants. Neild was on the field for only eight plays and had a hand in two sacks. “That’s a pretty good percentage,” defensive coordinator Jim Haslett said.

But for several reasons, it’s not likely the line will generate those numbers against the Arizona Cardinals and quarterback Kevin Kolb this Sunday — and maybe never again. The team’s defensive system is designed to allow its linebackers — Brian Orakpo, Ryan Kerrigan, London Fletcher and Rocky McIntosh — to get to quarterbacks. On passing downs, the defensive linemen are assigned to clear the path.

“We’re not going to get four sacks as a D-line every week,” Carriker said. “It’s ’Rak and it’s Kerrigan — it’s those guys who will get the sacks. It just worked out our way on Sunday.”

While the big bodies up front know they’re the first line of defense against the run, the team is placing a renewed focus on disrupting the quarterback. Last week, when Kerrigan received accolades for batting a ball, intercepting it and running it in for a touchdown, the television cameras only briefly showed the pressure on Manning, led by Washington defensive end Stephen Bowen, as Manning rushed the pass.

“Pushing the pocket, that’s one of the big [points of] emphasis for us this year,” Haslett said. “We want to make sure we get a push up the middle. We want to make sure we have somebody in the quarterback’s face, which we didn’t do a very good job of last year. So far, after the first game, I’d give us a good rating in that area.”

The team’s starting defensive linemen all came to Washington to be a part of Haslett’s system. Carriker was signed as a free agent in 2010 and Bowen and Barry Cofield signed in July. They all know their successes won’t be measurable solely by statistics, and a lot of their best work will likely go unrecognized. That’s the nature of the team’s 3-4 scheme.

“If it’s a run play, my job is to occupy,” Bowen said. “If somebody comes in my gap, you got to make the tackle. But my job is to make sure Rocky and London, those guys can float to the ball easy and make plays. We all have a job. Nobody should try to do more than their job and we should be fine.”

Players and coaches say that circumstances aligned nicely last Sunday, enabling the defensive linemen to reach the quarterback more in a single week than they managed in full months a season ago.

First, the talent upgrade is noticeable. Four of the six defensive linemen weren’t even a part of this team a year ago. Even though Neild is unpolished and made mistakes in his debut, he showed flashes of potential. Second, the returning players — Carriker and Kedric Golston — both say they’re more comfortable in the system and are reacting a lot more quickly. And all six are simply trying to play within the scheme.

“We’re all one unit,” said Bowen, who had a fourth-quarter sack last week. “There’s no superstars, nobody’s trying to showboat. Everybody’s just trying to win.”

Finally, Sunday’s game unfolded in a way that allowed the defensive linemen to play a big role. The Redskins had no sacks through the first two quarters. Washington led, 21-14, in the third quarter when the Redskins finally got to Manning. The Giants had to play from behind, relying more on the pass, which created more opportunities for the Redskins’ linemen and their nickel defense.

“Playing with a lead always helps in this league,” Haslett said. “You can turn it loose, especially a two-score lead, not just a lead.

The Cardinals present a different sort of challenge. Kolb topped 300 yards in his Arizona debut. He had long completions of 34, 48 and 70 yards, and three Cardinals wideouts had at least 60 receiving yards. Larry Fitzgerald can stretch the field and tight end Todd Heap will be a frequent target inside. Haslett called the Cardinals’ offense “electrifying.”

Coaches expect both Orakpo and Kerrigan to get to the quarterback more often.

Kerrigan is “going to be a work in progress,” Haslett said. “We need to work on pass rush. We need to keep emphasizing that. I thought he did a nice job in the run game. I thought he did a good job over tight ends. All that was good. Now we got to get him a little more polished on pass rushing.”