NHL

Rask mistake gives Rangers new life heading into Game 5

BOSTON — Sometimes it’s the smallest of things — say, about the size of a rut in the Garden ice — that can shift an entire playoff series, an entire season, an entire team’s destiny.

So maybe, just maybe, that supposed rut in the ice on Thursday night that forced Bruins goalie Tuukka Rask to fall over on his butt and allowed Carl Hagelin’s deflected dribbler to cross the goal line gave the Rangers just enough of a charge to shift the momentum, not just of that Game 4, but of the whole of this Eastern Conference semifinal.

At the very least, it gave the Rangers a heartbeat to come back in that game and win 4-3 in overtime, forcing the next step in this do-or-die sequence, Game 5 tonight in Boston with the Bruins still holding a 3-1 lead that suddenly seems less commanding in this best-of-seven contest.

RANGERS PLAYOFF SCHEDULE

“Bottom line is, all is forgiven, you don’t go back and dissect it,” coach John Tortorella said after yesterday’s practice in Westchester. “We talked about it before the game. We just wanted to get to Boston. We did. Now we need to try to win a game in Boston, and we’ll see where we go from there.”

For sure, that Hagelin goal — or more appropriately, that Rask gaffe — is all but distant memory unless the Rangers can back it up. Over the past two postseasons, they’re 6-1 in elimination games, including taking Games 6 and 7 of the first round this year against the Capitals.

“I guess in the back of your head you know there’s no turning back, there’s no option,” said Henrik Lundqvist, who managed to creep his postseason overtime record to 4-11. “You have to leave everything out there.”

It’s a strange phenomenon, these elimination games. Some say it speaks to the mettle of a team that fights them off, as the Rangers have done so dutifully.

“I think we find a way. We’re resilient. We’re not a team that’s going to quit,” said Brian Boyle, who scored the game-tying goal on a third-period power play. “But I don’t really know the exact answer.”

There wasn’t a direct answer from the team in light of Brad Richard’s healthy scratch, either, as the alternate captain and former Conn Smythe winner was benched in Game 4 in favor of some fourth-line grinders. If Tortorella’s goal with that move was to light a fire underneath his team, it didn’t work.

“Yeah, it was a little bit surprising,” Boyle said. “But all that other stuff that we can’t control, it has nothing to do with us. If you’re in the lineup, you have go out and try to help win a game.”

That effort wasn’t exactly apparent in a lifeless and scoreless first period, and the Blueshirts found themselves down 2-0 just eight minutes into the second. That’s when Hagelin fluttered a backhand, Boston defenseman Johnny Boychuk deflected it, and Rask fell over into what could be an infamous hole if the Rangers are willing and able to dig.

“We were ugly the first part of the game,” Tortorella said. “We end up finding ourselves after a fluky goal, and I think we played better.”

So maybe the answer to the question of turning tides lies somewhere between resolve and luck, somewhere in that strange place where history is pushed along by something like a rut in the ice.

“I have no idea how it all works,” Tortorella said, knowing enough to pack his bag and head to Boston, the opportunity for at least one more game.

bcyrgalis@nypost.com

Blueshirt brinksmanship

The Rangers are 6-1 in the past two playoff seasons when faced with elimination, with all but one game decided by one goal:

2012

at Senators, Game 6, W 3-2

Derek Stepan, Brad Richards and Chris Kreider score in a 10:24 span in the second period.

vs. Senators, Game 7, W 2-1

Second-period goals by Marc Staal and Dan Girardi hold up.

vs. Capitals, Game 7, W 2-1

Goals by Richards and Michael Del Zotto clinch series.

at Devils, Game 6, L 3-2 (OT)

Adam Henrique OT goal sends Devils to finals.

2013

vs. Capitals, Game 6, W 1-0

Derick Brassard’s second-period goal holds up, thanks to 27 saves by Henrik Lundqvist.

at Capitals, Game 7, W 5-0

Rangers win first-round series in rout with 35 saves by Lundqvist.

vs. Bruins, Game 4, W 4-3 (OT)

Kreider’s deflection of a Rick Nash pass at 7:03 caps a comeback from deficits of 2-0 and 3-2.