Josh Mahura and Adam Helewka scored power-play goals for the Rebels, who lead the best-of-seven series 2-0. Michael Spacek added the other.
Sam Steel, Cole Sanford and Adam Brooks all had power-play goals for Regina.
Trevor Martin made 35 saves for the win in net as Tyler Brown turned aside 28-of-32 shots in defeat.
Red Deer converted twice on four power plays while the Pats were 3 for 6.
Game 3 goes Tuesday in Regina at 7 pm on 620 CKRM.