Coming in on the back of a humbling 5-0 loss to rivals, the United States, Canada opened the scoring in the first period through Jennifer Gardiner. Daryl Watts and Kristin O'Neill netted in the second period, with Emily Clark scoring twice in the final period.
The rescheduled game, which was postponed last Thursday after members of Finland's team tested positive for norovirus, ended up being a face-off for the runners-up place in the group from which all five teams advance to the quarter-finals.
The United States topped the group, winning all four of their games, and will face hosts Italy in the last eight on Friday, with third-placed Czech Republic taking on Group B winners Sweden.
Canada meet Germany and Finland play Switzerland, who they defeated in the group stage, on Saturday.
With not a lot at stake, Canada were never likely to risk their 'Captain Clutch' with the knockout stages right around the corner. Five-time Olympian Poulin was injured in Monday's win over the Czechs and missed the loss to the US.
"She felt well, obviously not good enough right now to put her in the game (against Finland)," coach Troy Ryan said earlier on Thursday.
"An extra couple of days will do her justice."