With Peter Budaj making 34 saves and nine players getting their names on the scoresheet, the Canadiens beat the number one team in the Atlantic Division.
Budaj raised his record to 4-0 at the TV Garden.
The Canadiens got goals from Alexei Emelin (who was excellent), Max Pacioretty, Brian Gionta and Daniel Brière.
Tuukka Rask was beaten on three of the 18 goals he faced and chased to the bech after Gionta's power-play goal, 12 minutes into the second period.
Dougie Hamilton zinged one off Andrei Markov's skate for the home team's only goal.
The home team did nothing to get back in the game and were outshot 12-10 in the period.
Brian Gionta's ninbth goaof the season, on a Canadiens power play, ended Tuukka Rask's evening 12 minutes into the period.
Rask allowed three goals on 18 shots, a .667 save percentage.
Not trwo minutes later, Daniel Brière beat goaltender Chad Johnson on a breakaway. It was Brière's eighth.
Shots were 12-7 Boston.
Alexei Emelin got the Canadiens on the board with his first of the year, with massive George Parros parked in Tuukka Rask's crease.
Max Pacioretty made it 2-0 with his 23rd off a superb tic-tac-toe passing play with Brendan Gallagher and David Desharnais.
The 2-0 lead lasted barely longer than a minute.
Dougie Hamilton's point shot ticked off Andrei Markov past Peter Budaj to give the home team some life.
Shots were 14-13 for the Canadiens (DD line had six SoG).
The REAL rivalry
Yes, it's a big deal when the Canadiens play Toronto ... not least because the Leaf-blowers at Hockey Night in Canada get all hot and bothered about it.
And there was some hatred happening when Ottawa bounced the Canadiens out of the playoffs last spring.
But Canadiens-Bruins is a whole other level of loathing.
So many bitterly-contested playoff series. So much nastiness that carries over to the regular season.
From Maurice Richard breaking his stick on Hal Laycoe to Zdeno Chara running Max Pacioretty into a stanchion, tempers have boiled and blood has flowed when the bitter rivals hook up.
And between penalty whistles, we've seen some great hockey.
The teams' first meeting this season, Dec. 5 at the Bell Centre, was a comparatively tame affair. An injury to Bruins defenceman Johnny Boychuk cast an early pall over the game, which the Canadiens won 2-1, with Carey Price making 32 saves – including 16 in the third period.
That win boosted the Canadiens past Boston into first place in the Atlantic Division – a lofty perch they were to occupy for three days.
Boston currently sits comfortably atop the division while the Canadiens are scrambling for a playoff berth.
• Pre-game reading: The sad saga of Gino Odjick