Mandurah City will take on Olympic Kingsway in the decider to who will wear the night series crown.
City defeated State League rivals Subiaco 2-1 on Wednesday night to make the final which will be the sides first appearance in a night series decider since 2016.
It was a quiet first half with both sides heading into the main break without scoring.
John Baird's brace was the difference between the two sides converting from the penalty spot as well as drilling into the back of the net from close range.
Macedonia Park in Balcatta will host the decider on Saturday night with kick-off at 7:15pm.