Greg Chase and Kenton Helgesen also scored for the Hitmen (18-7-4), who extended their win streak to five games, while Brady Brassart chipped in with two assists.
Oliver Bjorkstrand scored the lone goal for the Winterhawks (22-5-4), who lost in regulation for the first time in nine outings.
Chris Driedger made 22 saves for Calgary as Portland's Brendan Burke stopped 28-of-31 shots.
OIL KINGS 2 TIGERS 1
EDMONTON — Two first-period goals and strong goaltending was all the Oil Kings needed to edge Medicine Hat for their fifth straight victory.
Reid Petryk and Dysin Mayo had a goal and an assist each for Edmonton (19-9-1), which lead 2-0 by the 17:12 mark of the first period, and Tristan Jarry made 38 saves.
Tommy Vanelli responded for the Tigers (18-9-3) at 19:46 of the first, but Jarry stopped 22 shots through the final 40 minutes to preserve the win for the Oil Kings.
Medicine Hat's Daniel Wapple turned aside 30-of-32 shots in a losing cause.