Sitting pretty in the early going and poised to coast to their season-high sixth straight victory, the Bruins finished the job Monday night with a thrilling 6-4 win over the Penguins at TD Garden when Brad Marchand ripped home his second goal of the night with only 1:57 remaining.

Did someone say coast? Hardly. The Bruins improved their record to a sizzling 11-1-2, but not before losing hold of a 3-0 lead in the middle period and having to fight back from a 4-3 deficit.

Finally, it was Marchand who snapped a 4-4 tie, racing down left wing after collecting a wide shot by John Marino that had a long carom.


Marchand galloped up left wing and zipped home a hard snap off the left wing that banged in off the far post.

Patrice Bergeron, with help again from Marchand (5-point night), knocked in an empty-net goal for the 6-4 final.

Other observations as the Bruins pack for Tuesday’s game in Montreal.

■  After blowing their three-goal lead, the Bruins pulled even, 4-4, on a Torey Krug one-time laser at 8:14 of the third. The shot was outstanding, but the beauty of the goal was Marchand’s puck control high in the zone, finally dishing down to Krug after eluding checks from Evgeni Malkin and Bryan Rust. Magical mitts.

“To be honest, I think I got a little lucky there,” said Marchand. “Malkin kind of caught me off guard, reaching in . . . I tried to get around the next guy [Rust] and Torey actually made a really good play, talking to me and letting me know he was open. Nice when it works out. But a lot of battles I don’t win. And you can always be better in those areas.”

Monday was a big night for Boston’s Brad Marchand.
Monday was a big night for Boston’s Brad Marchand.Matthew J. Lee/Globe Staff

Marchand finished 2-3—5, his second 5-point night of the season and improved to 10-18—28 for the season (all over 13 consecutive games).


■  The Bruins lost back liner Charlie McAvoy with 6:36 left when the third-year defenseman raced back to try to disrupt a Rust breakaway. Goaltender Jaro Halak handled the shot to keep the score tied, but the diving McAvoy slid hard into the crease and banged his head on the lower portion of the left post. He needed about 90 seconds to get up off his knees and finally make his way to the dressing room.

Coach Bruce Cassidy offered little information about McAvoy, who looked woozy as he left the ice.

“It happened so late, I have not gotten an update,” he said. “First thing you are worried about is a concussion, obviously, but I think it was just a cut. Krug also got cut. I am going to assume that the worst of the damage, some sutures . . . but I’ve got nothing else right now.

■  Unfocused and turnover happy (or sad), the Bruins submitted a dreadful second period and watched their 3-0 lead turn into a 4-3 deficit. How’d that happen? Above all, poor team-wide defense, allowing the speedy Pens to exploit the middle of the ice.

Down by three goals, the Pens reversed from a near pin with goals by Dominik “Toot” Kahun, Nick Bjugstad, Rust, and ex-Harvard defenseman Marino.

Bruce Cassidy wasn’t happy with the way his team played in the second period.
Bruce Cassidy wasn’t happy with the way his team played in the second period. Matthew J. Lee/Globe Staff

“Second period, I don’t think we did anything well at all,” Cassidy said. “We chased it the whole time. We’ve been on the other side of it — we did it to San Jose and the Rangers. You fight to get the puck back, and when you do, you get it out, change, and you are skating uphill the whole period.”


■  Marino’s goal, to bust the 3-3 tie, came on one of many breakaways, with Marino collecting the puck at mid-ice as he stepped out of the penalty box. McAvoy chased in his vapor trail, but Marino finished with a backhand tuck for the Pens’ first lead of the night.

■  Amid the mayhem of the second period, Cassidy dismissed the temptation to call a timeout, hoping his team would self-correct. One way to snap such a funk, he said, is to string together a couple of strong shifts, ideally through a forecheck that gets the other team on its heels.

Never happened.

“At this point of the year, there’s a little of bit of, ‘Let’s see this play out,’ ’’ said Cassidy. “We are in pretty solid position right now, maybe we needed to be kicked in the ass a little, you know, how do our guys respond? Do they sort it out themselves?”

■  Earlier in the second, the Bruins moved to the 3-0 lead at 4:22 when David Pastrnak ripped in his league-leading 14th goal of the season. That was enough for ex-Bruin Mike Sullivan, the Pens coach. He yanked starter Matt Murray and sent in Tristan Jarry for what looked like mop-up duty. Soon enough, the Pens were doing the mopping.

David Pastrnak was denied by Pittsburgh goalie Tristian Jarry on this first-period scoring opportunity.
David Pastrnak was denied by Pittsburgh goalie Tristian Jarry on this first-period scoring opportunity. Matthew J. Lee/Globe Staff

■  The Bruins had a 9-6 shot advantage when Marchand popped home the 2-0 lead at 13:05 of the first period. At the end of 40:00, the Pens had the one-goal lead and a 30-16 shot lead. Advanced math: 21-10 Pens advantage over 26:55. Bruins: deep sleep.


■  Jake DeBrusk’s goal for the 1-0 lead was his second in as many games, the first time this season he has struck in back-to-back contests. DeBrusk is streaky, and he has been snakebitten around the net this season. Perhaps his 2-in-2 will get his offensive mojo going. Little Louie averaged 22 goals in his first two NHL seasons.

■  Marchand popped in the 2-0 lead at 13:05 of the first. It’s no surprise when the LBO’H, with 100 points last season, puts the puck in the net. The surprise was team captain Zdeno Chara making a pinch down the left wing wall to force a puck to the net. Big Z picked up a deserved assist, giving him a 1-3—4 line over the last four games.

■  The DeBrusk and Marchand goals paced the first period for what looked like an easy 2-0 lead, but it took some sharp work by Halak to keep the Pens off the board. Only 2:59 into the period, the game scoreless, Jake Guentzel made a power move out of the left-wing circle for a stuff attempt, the agile Halak holding strong at the left post to keep it 0-0.

Bruins goalie Jaroslav Halak made some key saves in the early going.
Bruins goalie Jaroslav Halak made some key saves in the early going. Matthew J. Lee/Globe Staff

“We were very fortunate to capitalize on most of our opportunities and got key saves,” said Cassidy. “Our goaltender [Halak] outplayed theirs — that was probably the difference in the game.”


■  A sure sign of an inconsistent Pens team: they entered the night a mystifying 0 for 19 on the power play over their previous eight games. True, an injured Malkin was sidelined for seven of those games, but they still have too much talent in the lineup to be that inept on the man-advantage.

■  Kris Letang, the Pens highest-paid defenseman, coughed up the goal on DeBrusk’s opening strike. He lost it to DeBrusk outside the Pens’ defensive blue line, then did a poor job of chasing after DeBrusk. Even worse, tender Murray fell asleep on the shot, which DeBrusk let go from deep in the left wing circle. Bad puckhandling boo-boo. Worse netminding.

“Definitely feeling a little traction,” said DeBrusk, now with three goals on the season. “It kind of puts the mind at ease. It wasn’t the prettiest of goals, but I’ll take it — any time that I start kind of feeling like this it’s usually a good thing. I’ll just try to keep it rolling and . . . everyone says I am a streaky player, so hopefully I am streaking in the right direction.”

Kevin Paul Dupont can be reached at kevin.dupont@globe.com. Follow him on Twitter @GlobeKPD.