Miro Aaltonen scored the decisive goal, beating goalie Malcolm Subban at even-strength at 7:16 of the third period after Markus Granlund and Ville Jarvelainen scored on the power play in the first and second periods respectively.
Griffin Reinhart and Mark Scheifele scored less than a minute apart in the second to give Canada, widely considered the pre-tourney favourite to win gold, a short-lived 2-1 lead.
The Canadians will face Sweden on Saturday at 9:30 a.m. ET before travelling to Ufa, Russia the following day. They open the tournament Dec. 26 versus Germany at 4:30 a.m.