Zack Smith scored the Broncos' only goal in the first period, and Travis Yonkman made 33 saves in the loss.
Colton Teubert and Pat Krause scored power-play goals for the Pats to lift them to the victory, while Goalie Linden Rowat made 18 saves.
The Broncos have another chance to steal home-ice advantage from the Pats with a road split. Game two is tonight in Regina with all the action on The Eagle 94.1FM. The pre-game show will start at 6:30pm, and the play-by-play with Jon Keen and Ryan Switzer will be at 7:00pm.
All of the other WHL playoff series started last night. Calgary beat Moose Jaw 5-1, Lethbridge got by Brandon 2-1, Kootenay beat Medicine Hat on the road 5-2, Spokane topped Everett 5-2, Tri-City hammered Kamloops 6-1, Vancouver edged Chilliwack 2-1, and Kelowna got a crucial road win over Seattle 3-2.
All playoff matchups, with the exception of Moose Jaw and Calgary, play game two tonight.