The Manitoba Amateur Hockey Association instructed Manitoba's only Senior A team, the Winnipeg Nationals to playoff against the province's Senior B Champion in the best of 5 series. Winnipeg AAA won the 1948-49 Manitoba Senior B Playoffs Championship. The Nats played in the Manitoba-Thunder Bay League.
|Game||Team 1||Goals||Team 2||Goals||Date||Venue|
|1||Nationals||10||AAA||2||Friday, March 18||Amphitheatre|
|balance of series cancelled|
and advanced to the 1948-49 Western Canada Allan Cup Playoffs