Backup Kevin Lankinen took his place between the pipes.
Matias Maccelli, Max Domi and William Nylander, in his first game back from injury, scored for the Leafs.
Meanwhile, the Canucks were unable to solve Joseph Woll in the first period, with zero goals on 14 shots.
Demko, a Vezina Trophy finalist in 2024, has a .902 save percentage and 2.79 goals-against average with one shutout for the 32nd-place Canucks prior to Saturday night.
