Max Pacioretty, named on New Year's Day to the United States Olympic team, added an empty-net goal with 1:04 remaining. It was his second goal of the game.
P.K. Subban also scored and had three assists for Montreal while Carey Price stopped 32 shots to capture the win. Montreal had dropped its previous two contests.
Dallas had won five of seven and had earned at least one point in all seven of those games. Lehtonen, who came into the game with a 2.46 goals-against average, allowed five goals on 27 shots.