MONTREAL — Max Pacioretty had two goals, Dale Weiss scored on a penalty shot, and the Montreal Canadiens downed the rival Boston Bruins 5-1 on Thursday night for their fourth straight win.

Lars Eller and Jiri Sekac also scored for Montreal (12-4-1), which saw Sergei Gonchar’s debut after he was acquired Tuesday in a trade with Dallas.

Dougie Hamilton scored a power-play goal for Boston (10-8-0), which lost badly for a second game in a row after a 6-1 setback in Toronto on Wednesday night. The Bruins were playing their third game in four nights.

With Tuukka Rask pulled after allowing four goals on 16 shots in Toronto, Niklas Svedberg got the start for Boston and faced 34 shots. Carey Price made 21 saves for Montreal.

The Bruins came out of the first period with a 1-0 lead on Hamilton’s goal from Patrice Bergeron’s faceoff win only four seconds into a man advantage at 16:04.

Fatigue started to show in the second as Boston took three straight penalties.

The first was a penalty shot at 2:31, as Dennis Seidenberg lost the puck and then tripped Weiss. The Canadiens fourth-liner beat Svedberg between the pads.

Confusion behind the Boston net let Brendan Gallagher poke a pass in front for Eller, who scored his third goal in three games. Pacioretty added another less than two minutes later, at 14:57, on a one-timer off a feed from Weiss.

Pacioretty was at the crease to get a stick on a David Desharnais pass that deflected off Hamilton’s skate 5:09 into the third.

Sekac took a Nathan Beaulieu feed and went in alone on the left side to score on a wrist shot on a power play at 14:06. The goal ended an 0-for-27 run without a power-play goal for Montreal. It was only the Canadiens’ fourth this season, and three have come against Boston.

Gonchar had the Montreal power play looking livelier all night, although he wasn’t involved in the goal.