Juraj Slafkovsky — with an assist — Joel Armia and Josh Anderson also scored for Montreal (12-16-3), ending a two-game skid that started with a 9-2 rout to Pittsburgh last time out at home Thursday.
Cole Caufield, Nick Suzuki and Lane Hutson provided two assists each, while Sam Montembeault stopped 20 shots.
Dylan Cozens replied with the lone goal for struggling Buffalo (11-17-4). Ukko-Pekka Luukkonen made 15 saves on 21 shots, while backup James Reimer stopped all six that he faced after entering to start the third.
The lopsided loss came a day after Sabres owner Terry Pegula flew to Montreal for a team meeting amid the 10-game slide. Head coach Lindy Ruff also shouldered the blame following Saturday’s 5-3 loss to Toronto.
Armia added to Buffalo’s misery only 19 seconds into the game, capitalizing on a wide-open net after Sabres defenceman Owen Power mishandled the puck off the end boards. And things only got worse.
Laine buried three goals for the 11th time in his career, bringing the Finnish winger’s season total to six in seven games since returning from a knee injury.
Canadiens: Laine is coming as advertised. Montreal’s off-season acquisition scored his second and third goals on 5-on-3 power plays one minute 10 seconds apart midway through the second period, helping the Canadiens build a 5-1 lead. All six of Laine’s tallies are power-play goals from his office near the left circle.
Sabres: The owner’s visit didn’t inspire his team to a hot start. Buffalo recorded its first shot 10:05 into the game. The Canadiens had nine at that point, including two goals. The Sabres also couldn’t stay out of the box with five minor penalties in the first two periods — and Laine made them pay.
Fans littered the ice with hats before breaking out into a deafening ovation when Laine’s third goal was announced, something that’s becoming a regular occurrence at the Bell Centre. Then came the “Lai-ne!” and “Olé, Olé, Olé!” chants with eight minutes left in the second period.
Despite missing time, Laine is already tied for fourth in goals on the Canadiens with Anderson, Alex Newhook and Emil Heineman, all of whom have played 30 or more games.
Canadiens: Visit the Detroit Red Wings on Friday.
Sabres: Host the Toronto Maple Leafs on Friday.