The Cougars faced the Tigers in a soggy Saturday double header, with the rain holding off just enough to get play in at Fairfield Island.
Chiliwack edged the Tigers 4-3 in the first game and 4-2 in the second.
Cougar bats produce 10 hits in the opener, which went to extra innings.
Chilliwack could have sewn things up beforehand, had they not struggled with runs in scoring position.
The winning run came in the ninth inning when a hard-hit single by Peyton Nerbas drove Mike Rogers home.
Starting pitcher Blake Peeling tossed six innings, allowing three runs on seven hits while striking out eight.
Matt Lamb got the win, relieving Peeling for three scoreless innings.
Lamb struck out two.
Offence was harder to come by in the rematch.
The game was tied 2-2 going into the bottom of the sixth inning when a wild pitch by the South Okanagan hurler allowed base runner Ryan Petkau to cross the plate.
A sacrifice bunt by Nerbas added the insurance run. Top producers at the plate were Donovan Moorman, with the game’s only double, and Derek Riediger, who went 2 for 2 at the dish.
Riediger pitched as well, tossing a complete game with five hits and one earned run allowed.
He struck out seven.
The Cougars never got the Sunday double header played, with rain forcing forcing the West Kelowna squad to retreat back to their sunny home.
The Cougars are off to Kamloops this weekend for a three game series against the RiverDogs.
Home openers for the bantam and peewee AA Cougars were rained out.