Fiddler's goal came just 17 seconds in OT on the power play and he finished with two assists for a five-point game.
Chase Witala, Zach Pochiro, Jordan Tkatch, Alex Forsberg and Joseph Carvalho also scored for the Cougars (8-11-4).
Aspen Sterzer and Chase Souto had two goals each for Kamloops (6-12-3), with singles coming from Cole Ully, Tyson Ness and Aaron Macklin.
Ty Edmonds gave up six goals on 37 shots in the Cougars' net before his replacement, Brett Zarowny, made six saves. In the Blazers' net, Bolton Pouliot was pulled after giving up four goals on 14 shots. Taran Kozun took over and stopped 36 shots.
WINTERHAWKS 5 PATS 2
PORTLAND, Ore. — Taylor Leier's two goals paced the Winterhawks past Regina.
Chase De Leo, Nicolas Petan and Brendan Leipsic also scored for Portland (15-4-2).
Kyle Burroughs and Dryden Hunt replied for the Pats (11-10-0).
Jarrod Schamerhorn finished with 21 saves for Portland, a far quieter game than the 53 saves Dawson MacAuley was forced to make for Regina.