If the game was a tale of two halves, it was also a cautionary tale about Kelly's methods and the question of whether there is merit or madness behind them. In the second half, the Eagles looked a bit gassed on offense and their defense, which had been playing extremely well, began to leak at the seams. Redskins quarterback Robert Griffin III, playing his first game since knee surgery, got a little unrusty and the Eagles offense couldn't keep pace with the comeback he was trying to build.
In the end, though, the Eagles had just enough capital in the bank and Kelly is still the only undefeated coach in team history.
"We're excited. We played with a lot of energy. We made some mistakes, the coach included, but if we play hard, we have a shot and they played hard," Kelly said.
They played hard and they played fast, very fast, particularly in that no-huddle, no-way first half. Part of Kelly's plan is to make the other team so uncomfortable that it plays poorly. And to coach his own team to be confident that the speed of the game gives them a great advantage. When you have teams of essentially equal value and one of them is confident and one of them is unsure, the result is what happened in the first half Monday night in FedEx Field.
This isn't going to happen every week, because the Redskins looked spectacularly unprepared to defend the Eagles offense. Maybe it wasn't a fair test because they had nothing but Oregon film and vanilla exhibitions to work with. Fair or not, Washington stunk its way out of the game and couldn't quite recover even with a much better second half.
Other Eagles opponents this season will have the benefit of more useful film, and won't be taken by surprise by something like the formation in which the Eagles had just three offensive linemen tight to the football, and their other players on the line split wide and arranged as part of a pair of neat triangles. That was different.
"It's not a bag of tricks. It's football," Kelly said. "You try to put yourself in formations that are an advantage to you."
And, of course, the problem for the Redskins was that everything was different. Football players at this level have played all their lives at a certain pace. Run a play, huddle, run a play, huddle, run a play, rinse and repeat. The Redskins weren't tired when the Eagles rang up nearly 200 net yards in the opening quarter.
The win was made of more than just forcing the Redskins to sprint. The Eagles were very sharp and very effective, and the offense didn't have to really extend itself. Michael Vick's longest completion was 28 yards in the first half and, by comparison, that seemed like a bomb. Everything else was an underneath route or a quick dart to the sideline or a cutback run off misdirection blocking. Kelly's playbook wasn't groundbreaking, but it certainly chewed up ground.
Then there was LeSean McCoy, who was ridiculously good when he had to be. McCoy gained 115 yards just in the first half and carried the ball 20 times. As a team, the Eagles ran 53 plays in the half, compared to just 21 for the Redskins. In other words, McCoy had one fewer carry in the first half than Washington had plays.
The operative question after Monday's game, if questions are permitted, is whether the team in general and McCoy in particular will be able to hold up under that pace for a full season, or even for a full game when the outcome is still in doubt. As it was, the Eagles did sag after halftime, but perhaps only in comparison to the calliope ride of the first half.
The better question, though, is what the rest of the coaches in the NFL were saying to themselves after watching a pretty sharp compatriot like Mike Shanahan get embarrassed on national television. In all probability, they weren't very happy.
It could have been worse, should have been worse, except for that terrible fumble ruling on the opening drive of the game. Then the final minutes wouldn't have been in doubt, and then it wouldn't have mattered if the second half didn't match the first.
All anyone would have remembered was the speed of the blows and how a confident team playing at home suddenly felt it could no longer see them coming, let alone stop them.
Contact Bob Ford at email@example.com. Follow on Twitter @bobfordsports.