Dieno scored on the power play at 16:34 of the first period and then added another shorthanded at 16:49 of the second.
Grayson Pawlenchuk scored the eventual winner for the Rebels (19-16-2), who extended their win streak to five games, and Conner Bleackley chipped in with two assists.
Aaron Irving and Henrik Samuelsson responded for the Oil Kings (23-12-1), who dropped their third straight contest, and Tristan Jarry stopped 18 shots in defeat.
Red Deer went 1 for 5 on the power play while Edmonton failed to score on five chances with the man advantage.
GIANTS 4 BLAZERS 3
KAMLOOPS, B.C. — Cain Franson scored the tying and winning goals late in the third period to rally the Vancouver Giants to their win over the Blazers.
Franson got the equalizer at 16:38, and put the Giants (18-14-7) ahead with 1:41 remaining.
Alec Baer and Blake Orban gave Vancouver a 2-0 lead in the first period.
Aspen Sterzer, with two, and Sam Grist scored for Kamloops (9-25-4).
Payton Lee made 20 saves for the Giants, and Taran Kozun stopped 27 shots for the Blazers.
Vancouver was 1 for 3 on the power play, and Kamloops was 1 for 5.