Marchand completed the hat trick with a shorthanded goal to make it 4-0 at 7:10 of the second, scoring on the rebound of John Moore's initial shot.
"We've all been focusing on it more recently," Marchand said of getting to the dirty areas. "It's something that we've had to add to our game. We were getting a lot of shots early on in the season … and you know, the majority of the goals in this league are scored from there. So we had to get some more guys in front, get rebounds there again in front of the net, and focus a little more on being around there. Our group's been doing that since the break has been over, and it's really paying off for us right now."
Pezzetta made it 4-1 at 10:46 of the second with a turnaround shot after Brett Kulak's attempt from the point hit him in front.
"I definitely like playing against [Boston]," said Pezzetta, who has scored both of his goals this season against the Bruins. "It's a good challenge, and they're a great hockey team. … It's definitely a tough game to be a part of. There's lots of hard play, which I like, but obviously it wasn't the outcome we wanted today."
Lazar was credited with his second goal when Urho Vaakanainen's shot from the right point deflected off him in front at 10:19 of the third period for the 5-1 final.
"I'm just kind of seeing the game differently out there, where you know I'm seeing my plays, being strong on the puck, and it's nice to get rewarded for those chances," Lazar said. "But I think you guys know me. I'm kind of that blue-collar player that just plays hard both ways and I just hope for the best. I'm not going to reinvent the wheel out there. So to get rewarded playing the right way, it feels really good."
NOTES: Marchand has scored 33 shorthanded goals in his career, tying Brian Rolston and Guy Carbonneau for 14th in NHL history. … Only David Pastrnak (10) and Bergeron (seven) have more hat tricks than Marchand in Bruins history. … Moore left the game after sustaining an upper-body injury on Pezzetta's goal in the second period. There was no update postgame. … Boston goalie Tuukka Rask, who signed a one-year, $1 million contract on Tuesday, is expected to make his season debut against the Philadelphia Flyers on Thursday.