Luke Schenn and Nils Hoglander scored, and Thatcher Demko made 24 saves for Vancouver (4-7-3), which was also playing the second of a back to back after winning 6-4 at the Ottawa Senators on Tuesday. The Canucks were 4-1-1 in their previous six games.
"Right from the start we were chasing, and I don't think we came out the way we wanted," Vancouver forward Elias Pettersson said. "And they were hungrier than us to start."
Dach's second goal of the game at 15:02 of the third period put Montreal up 5-2 after the Canucks scored twice to draw within two.
"We knew they were coming off the back to back, we were coming off a back to back, so the start was crucial," Dach said. "And I feel like through 40 minutes, we dictated the play and we had a good team game going.
"We let off the gas a little bit at the start of the third, and they capitalized. It was good maturity for our group to kind of lock it down and finish the game strong."