Kosta Grozos was the undoubted star of the show, scoring a hat trick and grabbing an assist, while Samuel Silvera and Jarrod Carluccio also found the back of the net.
After a bright start, the early pressure paid off for the Wanderers when Silvera was upended just inside the penalty area. Grozos stepped up and sent the goalkeeper the wrong way from the spot to put the Red & Black 1-0 up.
It was 2-0 a few minutes later when Oliver Puflett whipped a dangerous ball into the middle but North Shore goalkeeper Ryan Wood was able to tip the ball away before Mohamed Najjar could apply the finish.
The Wanderers didn't have to wait long for their second goal with Silvera playing a neat one-two with Grozos on the edge of the penalty area before firing home from an acute angle.
Kosta Grozos was seemingly involved in everything the Wanderers did and got into a good position after a mazy dribble past three North Shore defenders.
North Shore responded and Wanderers goalkeeper Daniel Axford had to be on his toes to make two sharp saves in the space of a minute.
Puflet and Abdelranham Kuku combined to set up Grozos but a North Shore defender was able to block his shot.
However, Grozos was not to be denied and reacted quickest to a loose ball on the edge of the penalty area, blasting it into the top corner to get his second of the contest.
After the break, Grozos continued his excelled performance setting up Malcolm Ward after a good run, only for the right back's shot to go wide.
Grozos and Puflett would then have further efforts on goal before Grozos completed his hat trick slamming the ball from 20-yards out to make it 4-0.
Substitute Carluccio was lively in the final stages and had a few chances after getting behind the North Shore backline.
Carluccio showed dogged determination and would get his reward with five minutes left after smashing the ball past the keeper after a neat turn inside the penalty area.
There was even time for Carluccio to set up Richard Steward but the left back was unable to trouble the keeper.
Next weekend, the U20 side will play Northern Tigers after they defeated Hills Brumbies 3-1 in their semi-final.
The U18 team has also progressed to the Grand Final, coincidentally by defeating Northern Tigers at Sydney United Sports Centre.
After a scoreless first half, the Red & Black won 4-0 thanks to a double from Anthony Vastag, as well as goals from Yousef Sawalha and Alexander Lopez.
The U18s will play Central Coast Mariners in next weekend's decider.
Western Sydney Wanderers 5 (Kosta Grozos 9’ 42’ 68’ Samuel Silvera 15’ Jarrod Carluccio 85’)
North Shore Mariners 0
Western Sydney Wanderers: Daniel Axford, Malcolm Ward, Lachlan Campbell, Richard Stewart, Daniel Wilmering, Abdelrahman Kuku, Joshua Bartolotto (Zachary Duncan 66’), Kosta Grozos (Mohamed Al Taay 69’), Oliver Puflett, Samuel Silvera (Brandon Stojcevski 46’), Mohamed Najjar (Jarrod Carluccio 60’)
Unused substitutes: Jack Groeneveld