Karlsson scored his second of the game on a backhand at 17:28 for the 6-0 final.
"That's what we were talking about before the third, to have the mindset to score more goals, play the same way," Karlsson said. "Be aggressive, but also be aware. I think we executed very well and, overall, played a really good game."
Karlsson has seven points (four goals, three assists) since Pacioretty moved to his line with Reilly Smith three games ago.
"It's a message, right? That it's not working with what we have right now," he said. "We want to mix it up and you just want to play the best you can. So far it's been working with [Pacioretty] for us."