We have known for some time this Rangers team just wasn’t the same as the two preceding it that made successive, honest, deep runs at the Stanley Cup that did the franchise proud.

That sense was driven home with utmost clarity with the first-round Game 4 debacle at the Garden on Thursday in which the Blueshirts were nothing more than a shell of themselves — or a legitimate playoff squad — in a shocking 5-0 defeat by the Penguins that left the squad on the precipice of its earliest elimination since 2011.

There is no shame in losing to a better club or losing a first-round playoff series. But the Rangers’ lack of work ethic and absence of visible pride throughout this beat-down — which began with a goal 69 seconds into the match and in which Henrik Lundqvist suffered the quickest hook of his 115-game playoff career — heaped dishonor onto the sweater.

Lundqvist, yanked after allowing four goals on 18 shots in 26:04, was no innocent bystander here. The netminder, beaten on the first one after allowing a bad rebound and on the third one on a short-side breakaway after he had been done in on a double deflection for the second one, didn’t come up with a big stop until the early moments of the second period, when it was already 3-0.

One goal and a couple of minutes after that, The King was lifted, his robes in tatters, his crown askew.

“If you give up four goals on 18 shots, you expect a change might be happening. Also, it’s a series, so we have another game coming up [Saturday in Pittsburgh],” Lundqvist said. “I’ve got some time to think about what I was doing wrong.

“Was it a couple of tough plays? Yes. But I did not play it the way I want to play it. I need to be better. As simple as that.”

The Rangers played like dead men skating. The Penguins exposed them in every conceivable area: took away the Blueshirts’ time, took away the Blueshirts’ space, and stripped the Blueshirts of their essence.

Who were those guys? It beats me.

True enough, the Rangers have laid some eggs on the Garden ice during each of the last two playoffs, or even in each of the last four, through which they have won eight rounds. Bad things happen sometimes to good teams.

But this was different. Shockingly so. The Rangers — who actually did seem as if they were in a good place when they came home with a split of the opening two games in Pittsburgh — looked like they didn’t belong in the series, like they didn’t belong in the playoffs.

This was a total eclipse of the heart on top of a systems-wide breakdown that infiltrated from player to player, line to line, and defense pair to defense pair. No one — other than perhaps relief netminder Antti Raanta — was immune from infection.

So where to begin with this fiasco? Where to begin and where to end with this group that etched itself into franchise history with these Games 3 and 4 defeats stretching the overall playoff home losing streak to an unprecedented five games through which the Rangers have been outscored by an aggregate 18-3?

Where to begin and where to end with this group that over the last two tournaments has gone those five consecutive games at the Garden without scoring a single, solitary 5-on-5 goal, the streak ballooning to an unfathomable 302:25?

Want to start with the specialty teams? Fine by me. Three power-play goals for the Penguins, none for the Rangers. Through four games, Pittsburgh is 7-for-19 on the power play while the Rangers are 0-for-16 with the man-advantage (and 1-for-1 with a two-man advantage). What, you expected the penalty-killing follies to disappear with the start of the playoffs?

It is a fool’s errand to attempt to break this down technically. The Rangers were two steps and two moves behind the Penguins from the get-go. They were emotionally empty from the drop of the first puck. It appeared as if they grew old overnight, all of them and all at once.

So now it is on to Pittsburgh, the Rangers facing the same 3-1 deficit they overcame against the Penguins two years ago; the same 3-1 deficit they overcame against the Caps last spring.

But this year’s team isn’t last year’s and it isn’t the one from two years ago, either. That’s where we came in, isn’t it?

And that’s also why the Rangers are likely to go out quickly this time. Fact of the matter is, anything else would be even more shocking than what happened at the Garden in Game 4.