Max Gerlach and Eric Florchuk each had two goals for Saskatoon (31-13-8-0). Gary Haden had four helpers, and Ryan Hughes has three assists.
Stelio Mattheos, Luka Burzan and Cole Reinhardt scored for Brandon (22-21-3-4).
Dorrin Luding kicked out 25 shots for the win. Ethan Kruger made 30 saves for Brandon.
Saskatoon went 2-for-3 with the man advantage while Brandon went 3-for-6.
The Blades win allowed the Raiders, the top team in Canadian junior hockey, to become the first WHL team to clinch a playoff berth.
Prince Albert has the best record in the Canadian Hockey League (43-7-0-2) and has been ranked in the Top 10 for 17 weeks.
The Blades are back in action Wednesday when the Moose Jaw Warriors travel to Saskatoon.
Moose Jaw is six points back of Saskatoon in the battle for second place in the East Division with four games in hand.
— With files from The Canadian Press