Tied for wins and points through 72 regular-season games, the two clubs were forced to play a tie-breaker game for the eighth and final spot in the Eastern Conference.
Josh Morrissey, Reid Gardiner and Dakota Conroy each had a goal and an assist for the Raiders, who won three straight games to jump over Red Deer. Collin Valcourt scored once.
Wyatt Johnson, Rhyse Dieno and Evan Polei supplied the goals for the Rebels, who will miss the playoffs for the second time in the past three seasons.
Prince Albert's Nick McBride made 27 saves for the win as Red Deer's Patrik Bartosak turned aside 42-of-46 shots in defeat.
The Raiders will face the top-seeded Edmonton Oil Kings in Round 1 of the WHL post-season.