Down by a goal, the Rockets rallied to force the extra frame but it was the Giants who came up big in overtime.
Heading into the third, Kelowna trailed 3-2 with back-to-back goals from Gabriel Sturzc.
With just under 10 minutes left in regulation, veteran Rocket Jake Lee posted his 100th WHL regular-season point with an assist on Colton Dach’s game-tying goal that forced overtime.
In the extra frame, Lee managed to nail the post 10 seconds in but the play then shifted to the Rockets’ zone where the Giants’ Zack Ostapchuk ended things just 30 seconds into overtime, jamming the game-winner past Boyko.
The Giants outshot the Rockets 34-23 and 4-0 in overtime.
Talyn Boyko stopped 30 of the 34 shots fired on him in his seventh straight start for the Rockets.
Vegas Golden Knights prospect Jesper Vikman, a thorn in the side of the Rockets so far this season, turned aside 20 of 23 shots.
Kelowna was 1-for-2 on the man advantage, while the Rockets’ penalty kill held Vancouver 0-for-1 on the power play.
The Rockets now sit in second place in the B.C. Division with 36 points and a record of 16-9-1-3 on the season.
Kelowna won’t have to wait long for a chance to avenge the loss as they host Vancouver, Friday, Jan. 7.