SUNRISE, Fla.–Unlike a year ago, the Bruins are clear underdogs in their second round matchup against the Florida Panthers, the team that junked the B’s dream season last year.

But on Monday at Amerant Bank Arena, the B’s served notice that they would not be an easy out.

The Bruins allowed the first goal of the game and then scored the next five to take Game 1, 5-1, to take a 1-0 series lead.

They leaned on some Dad strength as well as youthful exuberance to take the victory. Brandon Carlo, who made it to the rink two hours before puck drop after the first of his son (Crew is his name) in Boston, while rookies Mason Lohrei and Justin Brazeau scored, as did Morgan Geekie.

And, of course, Jeremy Swayman did his part. Forty-eight hours after closing out the Toronto Maple Leafs, he was brilliant again in victory, making 38 saves.

The B’s had a good opening 20 minutes, which were scoreless. But it took them a few minutes to get their footing.

Right off the bat, the Panthers had a glittering scoring chance when Jeremy Swayman gave up a big rebound on a long Sam Reinhhart shot, but he somehow recovered to make a tremendous save on Anton Lundell’s follow-up that seemed destined for the back of the net.

But eventually, the B’s got going. Unfortunately for them, Sergei Bobrovsky was airtight in the first, if occasionally off balance. His best save came when David Pastrnak stole the puck from Aaron Ekblad in the Florida zone and created a clean break-in for himself. It looked like the five-hole was open, but Bobrovsky got his glove on the offering.

The B’s outshot the Panthers 13-8 in the first and the most promising sign was that Pastrnak was highly involved. He took seven shots, landed four and had a backcheck that thwarted a Florida scoring chance in the first.

The Panthers started to get the better of the chances early in the second and they broke the ice at 11:45 on an unforced Bruin error. The B’s appeared to be in control of the puck in their zone for a breakout when Charlie McAvoy’s bank pass was behind John Beecher. Sasha Barkov was more than happy to pounce on it and dish it to Matthew Tkachuk, who ripped over Swayman’s blocker.

But the B’s tied it up just 1:06 later. Pastrnak fed it down low to Pavel Zacha, who couldn’t do much with Bobrovsky coming out of his crease to play him, sliding underneath him to take his legs out. But that left the cage wide open for Morgan Geekie to tie it up.

The B’s then took the lead at 16:17 on Mason Lohrei’s first career playoff goal. Parker Wotherspoon fed him down low on the left and from the bottom of the circle, the rookie sniped a wrist shot over Bobrovsky’s near shoulder, a kind of shot that makes you feel the B’s have something special in the kid.

Then the B’s stunned the crowd to take a two-goal lead with 20.6 seconds left in the period. Carlo made it 3-1 after Trent Frederic hustled to catch up to a clear into the Florida zone and dished to Charlie Coyle. With Brad Marchand creating havoc in front of the net, Coyle passed to Carlo and he beat the screened Bobrovsky from the top of right circle.

The Panthers stormed the Boston zone to start the third period and Swayman had to be brilliant to keep it to a two-goal. It got bad enough that, at 5:12, coach Jim Montgomery called his timeout to get his team’s attention.

It worked wonders. The B’s not only turned back the Panther attack, Justin Brazeau stretched the lead to 4-1 at 7:13. James van Riemsdyk sent Brazeau away on a breakaway and he used his long reach to go to his backhand and lift it over Bobrovsky.

That pretty much ended it, though Jake DeBrusk finished it off with an empty-netter.