In their biggest game of the year for their frame of mind as much as for the standings, the Bruins did what their coach told them to do.

They woke the bleep up.

The B’s shook off three one-goal deficits and took their first lead of the game with 2:31 left in the game on Pavel Zacha’s goal to beat the Florida Panthers, 4-3, in Sunrise, Fla.

The B’s the were able to kill the 6-on-5 for over two minutes to capture the much needed win.

It wasn’t perfect, but it was playoff-style hockey, physical and nasty, and the B’s came out on top for a change, snapping a two-game losing streak that had their coach steaming mad.

After being read the riot act from coach Jim Montgomery for a sleepy start to Monday’s practice, the B’s duplicated that effort on the first shift of the game and found themselves down a goal just 27 seconds in.

It was a patented Panthers’ shift to start the game. Vladimir Tarasenko went in on the forecheck and delivered a blow that knocked Morgan Geekie’s helmet off. He chose to leave the ice instead of picking up the bucket and the B’s were scrambling. Eventually, Sasha Barkov sent a bad angle shot toward the net. Jeremy Swayman couldn’t glove it and got through him to Evan Rodrigues, who had a tap-in.

Matthew Tkachuk then suckered Parker Wotherspoon into taking a roughing penalty with a low reverse hit and the B’s went on the penalty kill. They survived it, and then a few more minutes of Florida pressure before they themselves went on the attack.

After controlling the play for a good chunk of the period, the B’s tied it up with 2:37 left in the first on a strong shift. It started with a good reverse hit by David Pastrnak on Tkachuk along the left wall and he got the puck to Zacha a few feet away. Zacha fed Matt Grzelcyk at the left point and, with the Panthers overloaded to left side, Grzelcyk dished to Charlie McAvoy. McAvoy stepped into the right circle and blasted a slapper past Sergei Bobrovsky for his 10th of the year, snapping a 10-game pointless streak.

But with the B’s lately, good things happening usually means a bad thing is right around the corner and they could not get out of the period even. Brandon Carlo retrieved a puck behind his net and, as he was looking to move it up to Hampus Lindholm, he fell and missed his mark. Dmitry Kulikov collected it and fed Eetu Luostarinen, who slipped it across the top of the crease for a Sam Reinhart redirect past Swayman with 1:04 left in the period.

In the second period, the Panthers tried to flex their muscles. After a particularly nasty scrum, Sam Bennett held Lindholm’s head down just long enough to anger the mild-mannered Swede. Lindholm came up swinging and tagged Bennett with a left and the two went at it for Lindholm’s first career fighting major.

A little later in the period, 5-foot-9 Brad Marchand dropped the gloves with 6-foot-5 Niko Mikkola, who then wrestled Marchand to the ice. The combatants only received matching minors.

While the rough stuff is supposed to favor the Panthers, the B’s tied it again at 15:59. Marchand created a turnover on the forecheck to get the Panthers chasing. The puck eventually came around to McAvoy on the right wall. He made a move to control the puck and then found a wide-open Pastrnak in front of the net. He was able to just get it over Bobrovsky’s left pad for his 45th goal and 100th point on the season. Pastrnak became the first Bruin in 30 years to post back-to-back 100-point seasons since Adam Oates did it from 1992-94.

The B’s were playing some decent hockey in the third period until one mistake blew up on them. On a promising looking rush, Charlie Coyle attempted a shot from deep on the right wing that missed the net and sent the Panthers off on an odd-man rush. Carter Verhaeghe beat Swayman with a wrister from the left circle at 9:53.

The Panthers threw the B’s a life-line when Kevin Stenlund slashed McAvoy but Marchand wiped out the power play with an interference penalty.

The B’s got another chance when Rodrigues shot the puck into the crowd with 5:43 left in the third. And for the third time in the game, the B’s tied it again. As the B’s were changing out units, Marchand made entered the zone through a couple of Panthers and fed Trent Frederic for a one-timer goal from the slot with 4:22 left in regulation, his 18th goal, a career high.

Then the B’s got some puck luck to take their first lead with 2:31 remaining in regulation. Pastrnak whipped a pass toward the net that went off Zacha’s skate and in for the 4-3 lead.