WASHINGTON — They have been getting away with lax work on the defensive side of the puck pretty much since the season commenced.

The Rangers have been saved by their elite offensive talent at one end and by the elite work of Igor Shesterkin at the other end of the ice.

But not in this one, not against a heavier team and a better opponent such as the Capitals. Instead, this was one in which their opponents forced the careless — and even at times casual — Blueshirts to pay.

Truth is that Tuesday’s 5-3 empty net-aided final score was kind to the Rangers, whose joyride through inferior opponents came to a halt after encountering a dead end against the champion Panthers at the Garden last Thursday.

Battles were lost. The middle of the ice was barely defended. Odd-man rushes came in waves after poor decisions with the puck that led to turnovers in all the wrong places.

The defeat was an exception, the Blueshirts now 6-2-1, but the porous work away from the puck has been the rule.

The Rangers — who, according to Natural Stat Trick, were out-chanced 34-14 and by 15-8 on high-danger opportunities by the Capitals — have not defended nearly as hard or as consistently this year as they did last year. The eye test suffices.

“So no, tonight, definitely not, the answer to that is that we needed to defend much better than what we did with much more attitude than what we did,” head coach Peter Laviolette said when asked if his team has defended hard enough consistently enough. “I think there have been times this year where we have defended pretty well but I don’t think we defended really well.

“You can go back a couple of games against Florida, I don’t think we defended very well against that game, either.”

The Rangers were a mess in their own end of the coverage. K’Andre Miller had a dreadful night, giving the puck away multiple times in his own end while also being beaten to the net for a goal after losing a puck battle.

Indeed, after speaking in positive terms about the Miller-Adam Fox tandem following the morning skate, Laviolette broke them up after the second period, going back to the old standby Ryan Lindgren-Fox and Miller-Jacob Trouba pairs.

“I thought it was off the mark a little bit tonight,” said the coach. “It was to try and switch it and give it a look. We’ll figure it out.”

Filip Chytil was the Rangers’ best forward and his line with Will Cuylle and Kaapo Kakko had its moments.

But Mika Zibanejad, whose ice time has been steadily diminishing, had a very tough night and the Artemi Panarin-Vincent Trocheck-Alexis Lafreniere unit was ordinary other than for a handful of puck-possession shifts. Lafreniere made little impact in this one.

The Rangers did generate enough opportunities against Logan Thompson but they played as if on a treadmill to nowhere, yielding more than they took.

They were down, 2-1, at the 5:10 mark of the first and 4-2 at 4:30 of the second. Shesterkin held the Capitals scoreless the rest of the way but the Blueshirts could not come back.

They didn’t lose it at the offensive end, they forfeited their two points because of sloth in the neutral and defensive zones.

Yes, it is October, yes, the Rangers are good, but this is not the template for a championship team.

A year ago the Blueshirts were 14th best in the league surrendering scoring chances per 60:00. Now they are sixth worst. A year ago, the Rangers were ninth-best allowing high-danger chances. Now they are fourth worst.

This is not a template for a championship team.

“There is detail to defense. There is definitely detail to defense,” said an annoyed Laviolette. “But defense is attitude and there’s a lot of compete that goes into defense, the battles that have to take place.

“For me, they’ve been off for a couple of games out of the last three. I think any good team starts with good defense and the way they defend and the purpose defensively, it leads to getting pucks out of your end and leads to playing offense.

“Battles [are] defense. If they have the puck, that’s defense. It could be forecheck, it could be neutral zone defense, it could be faceoffs, it could be defensive zone coverage. It wasn’t good tonight,” said the coach. “There’s no question.”

The thing is, 6-2-1 aside, it was not the first time.

Ottawa at the Garden on Friday.