Kerby Rychel and Tyler Bertuzzi each scored twice for the Guelph Storm in a 5-2 win over the Edmonton Oil Kings at the Memorial Cup.
Brock McGinn also scored for the Ontario Hockey League champions.
Henrik Samuelsson and Ashton Sautner replied for Edmonton, who won this year's Western Hockey League title.
Storm goalie Justin Nichols made 37 saves for the win. Edmonton's Tristan Jarry stopped 27 shots in the loss.
The Oil Kings play their second game in as many days when they face the host London Knights on Sunday. The Knights opened the tournament with a 1-0 loss to the Val-d'Or Foreurs.
The Memorial Cup has been handed out to Canadian junior hockey champions since 1919 and awarded in memory of those who died in the First World War. The tournament includes the Western, Ontario and Quebec major junior league champion as well as the host team.
The club with the best record after the preliminary round earns a bye to the final May 25. The second- and third-place teams meet in the semifinal May 23.