Pacioretty scored twice to lead the Canadiens to a 5-2 victory over the Maple Leafs on Wednesday night and emphatically avenge a 6-0 home loss on Feb. 9.
There was bad blood between the longtime rivals in that previous meeting when an alleged biting incident involving Mikhail Grabovski and Pacioretty took place.
"The coaches talked to us before the game about sticking to our game plan and not getting sucked into the emotions of the game," Pacioretty said. "I think we did a great job of that."
Defenseman Josh Gorges echoed Pacioretty's take on the rematch.
"There's always a lot of different ideas, different emotions especially after the last way we played these guys about how do we get back," he said. "It's not about grabbing somebody and jumping them and feeding them punches because that really doesn't do us any good in the long run.
"It may feel good for a few minutes if that opportunity did ever come, but ultimately two points always feels better."
Gallagher scored his sixth of the season at 9:08 of the third period to break a 2-2 tie. Pacioretty clinched the win for Eastern Conference-leading Montreal (13-4-3) with his sixth at 14:26, and Gionta added an empty-net goal with 2:26 left.
Since being shut out by Toronto, the streaking Canadiens have gone 7-0-2. They outshot the Leafs 40-23 before a crowd of 19,625 -- the largest in Toronto this season.
The Maple Leafs, who earned a 2-1 win at Montreal in the season opener, fell to 4-5 at home overall.
"The Maple Leafs played two terrific games at the Bell Centre and we knew we had to bounce back from those type of games," Canadiens coach Michel Therrien said. "We certainly played a great team game and stuck to our plan, and we were controlling our emotion to play that game.
"Right from the get go I thought our guys were ready to play, and we set the tone. They tried to be physical on us but I was not afraid of that. We just kept focusing on the things we had to do to be successful."
Maple Leafs goalie Ben Scrivens made his eighth straight start and kept his club in the game, finishing with 35 saves.
"We were flat, flat, flat, flat," Maple Leafs coach Randy Carlyle said. "It looked like at times that we were playing in our boots and they were playing on skates.
"We just didn't get anything going for ourselves. I don't think there's any way to paint it pretty and I'm sure you guys will give us a lot of help."
Ryder didn't figure in the scoring but wore his usual No. 73 after rookie Gallagher gave it up to him. Ryder has worn No. 73 since breaking into the NHL in 2003. Gallagher wore No. 11.
Montreal controlled much of the first period, outshooting the Leafs 12-4, but McLaren opened the scoring with his second goal at 13:44.
Defenseman Alexei Emelin tied it with his first at 16:56 before Toronto's Mike Brown received a major penalty for checking from behind. He was ejected after he hit Gorges in the final minute of the period.
Pacioretty put Montreal ahead on the power play at 4:17 of the second. Scrivens attempted to deflect P.K. Subban's point shot to the corner but it deflected in off Pacioretty for his fifth.
Toronto had a prime chance to tie it when Grabovski was awarded a penalty shot at 11:45 after he was hauled down by Emelin. But Grabovski couldn't beat Price to the stick side on the attempted deke.
MacArthur tied it at 15:47 with his fifth.
This was the third of five meetings this season between the teams. ... James Reimer served as Scrivens' backup after being added to the active roster earlier Wednesday. Reimer had been out since sustaining a knee injury Feb. 11 against Philadelphia. G Jussi Rynnas was reassigned to the AHL's Toronto Marlies. Reimer is expected to start Thursday at the New York Islanders. ... With Rafael Diaz (concussion) out, Montreal D Tomas Kaberle suited up against his former team. ... Maple Leafs D Mark Fraser came into the game leading the NHL with a plus-14 rating.