PHILADELPHIA (973espn.com) - There is a fine line between success and failure in the NFL and sometimes your opponent is the ultimate arbiter in deciding which side of the that boundary you're going to reside on in any particular week.

How else can you explain an offense which gained a total of 1,176 yards through four games, piling up 519 during a 39-17 rout over the woebegone New Orleans Saints on Sunday?

Rob Ryan's bunch was exactly what Philadelphia needed, a glorified scrimmage where mistakes weren't going to be magnified. Dropped passes, missed blocking assignments, interceptions in the red zone ... who cares? An actual margin of error in the NFL is rare and the Eagles and their embattled offensive line got one at the most opportune time.

Jason Peters foreshadowed the resurgent line's performance on Thursday of last week when the big man told reporters to "just watch on Sunday."

(Listen to John McMullen discuss the Eagles offensive line and more from the Eagles win over the Saints)

What we saw was 186 rushing yards and perhaps the beginning of the vision Chip Kelly had when he brought together DeMarco Murray and Ryan Mathews in the same backfield.

Tweaking the inside/outside zone-running philosophy helped as Kelly let quarterback Sam Bradford get under center 17 different times, which allowed the runners to get downhill immediately and pick and choose the running lanes by giving them an extra second to digest what was going on in front of them.

Conversely, the offset running philosophy out of the shotgun forces the backs to go east and west before hitting the hole and also put tremendous pressure on the guards and center Jason Kelce to pull and make blocks in space against penetrating defenders.

Kelly, however, denied there was much of a change on Monday.

"I don't know if you watched the same game we watched, we ran sweep more than any play we ran there," Kelly claimed. "We had the ball outside more than I think we have had any game we've played this year. We ran the ball outside more than in any game we played this year."

Really?

Well, the film says something different as Kelly continued to play the execution card, perhaps because he eventually wants to get back to the outside zone stuff on a more consistent basis.

"We just blocked better in the run game," Kelly claimed. "And obviously if we can get our run game going, then our pass game with our quick game and our play-action passes off of that, I think we kept Sam clean, gave him an opportunity to throw the football. But, it starts with us being able to run the football, and we did a good job with that."

To some degree Kelly was right because Peters was back playing at an All-Pro level while his bookend on the right side, Lane Johnson, was also very good despite playing through a sprained MCL. Kelce also finally played up to his reputation for the first time in 2015.

"We thought Jason graded out really well and played really well, but I thought he played well versus Washington, also," Kelly said. "He has gotten better as the season has gone along, but he's played -- in the last two games, he's played at a really high level."

All that said, there was certainly a different look to certain runs with Bradford under center because the formation itself changes the angles and gives Murray and Mathews more options if the play is not blocked as it was drawn up.

Once things started going in a positive direction Kelly was able to get back into his comfort zone and call more of the outside zones he feels comfortable with, something Matt Tobin admitted.

"In the second half, we started going outside zone and sweeps," the right guard said, "Going into it, we just wanted to be physical the whole game and knock them back."

There are still problems to work out, however, because at this point Bradford under center is almost a sure sign that the Eagles are going to run the football, a tendency that will certainty be recognized by the better defenses in this league.

Sunday, though, was about building confidence and getting the offense back in a positive state of mind. The bells and whistles can come later.

-John McMullen covers the Eagles and the NFL for 973ESPN.com. You can reach him at jmcmullen44@gmail.com or on Twitter @JFMcMullen