The Rangers were deep-sixed, in more ways than one.

After a 102-point regular season and a dispatching of the Montreal Canadiens in the first round of the Stanley Cup playoffs, the Blueshirts' season is over.

After dropping three games in Ottawa — Games 2 and 5 in overtime after losing late leads — they were unable to win a critical game at Madison Square Garden Tuesday night. They were eliminated from the postseason in the second round with a 4-2 Game 6 loss to the Senators.

“It’s extremely disappointing,” said Henrik Lundqvist, who had won 10 straight elimination games at the Garden. “When you think about this series, their six-on-five play was the big difference. We had a chance to win a couple in Ottawa and that hurt us big-time. We played well enough to win a lot of games; sometimes it’s not about playing your best game, it’s about finding a way to win. They did that better than we did. We put ourselves in a position to win in almost every game, we just didn’t get it done. It’s going to hurt for awhile.”

Down 3-1 after two periods, Chris Kreider busted past defenseman Cody Ceci and cut the lead to a single goal at the 53-second mark of the third, giving the Garden faithful hope.

For the first time all night, the Senators, who led 2-0 after a dominant first period, looked a little rattled, and with 13:31 left were whistled for a too-many-men on the ice penalty. It was the most pressure on four power plays of the evening for the Blueshirts, but Craig Anderson, who finished with 37 saves, was there when needed.

The Senators came out strong. On the first goal, at 4:27, all five Rangers were below the hashmarks, allowing Erik Karlsson’s feed to an open Mike Hoffman for a deflection past Lundqvist for a 1-0 lead. The Rangers had scored first in all five previous games.

The first turning point came when Derick Brassard’s stick caught Mats Zuccarello in the mouth, drawing a four-minute double-minor at 8:35, which gave the Rangers a golden opportunity. But their man-advantage was predictable and unsuccessful with point shots, and the air came out of the building.

“We came out slow, it’s as simple as that,” said Ryan McDonagh. “We have nobody to blame but ourselves.”

Mark Stone forced Brendan Smith to back up and he whipped a high stick-side wrister past Lundqvist at 14:44. Coach Alain Vigneault tried an offside challenge, that failed, and the Senators had their first two-goal lead of the series.

“It’s not just this game, it’s the whole series in general, we kinda gave it away, easy goals” said Zuccarello. “We had leads, games in our hands, and we gave it away easy. It’s tough to swallow.”

The Rangers had been strong in second periods, but the Senators were quicker to pucks, found lanes to shoot, and the “Let’s Go Rangers” chants were fewer and fainter.

The Rangers got one back when Zuccarello found Mika Zibanejad with a headman pass to send him in alone and he beat Anderson under his glove side at 13:32.

But Karlsson delivered the dagger and the eventual winner. He restored the two-goal lead when he took Bobby Ryan’s backhand pass and snapped a high shot past Lundqvist at 15:53.

“It’s a good team over there, they played real strong games and they had the magic, sometimes you’ve got to have a little of that,” said Derek Stepan. “Individually, I’m disappointed, and ashamed and flat-out embarrassed that I wasn’t able to find my game. But I’m real proud of this group.”

More Rangers