Cookstown faced Magherafelt Sky Blues for the third time this season hoping to maintain their unbeaten run against their local rivals.
Although scrappy, Cookstown settled into the game much quicker and Larmour was close to latching onto a through ball by Arrell.
The deadlock was broken on the ten minute mark when Devlin intercepted and ran half the pitch before the defender conceded a penalty.
Up stepped Arrell, fresh off scoring five for his school during the same week, to dispatch the first of his three in the match.
Magherafelt had a chance to draw level but their midfielder fired high over the bar when well placed.
From the resulting goal kick, Young, whose handling and positioning was superb all night, dispatched the ball to Thom who found Dobson.
He squared to it Arrell who released Larmour behind the defence and he calmly slotted home is first of the night.
A throw-in from Devlin was flicked on by Larmour and headed home by Arrell for his second of the night.
McMullan was supplying good balls to the forwards on the left hand side and Kelly, Dobson and Donnelly were keeping their shape well in the middle of the park.
The coaches reiterated that the game was not over given that the wind was now fully in the face of Cookstown but praised them for the way they dealt with the conditions.
Dingley and Hughes came on to freshen up the midfield as a long half was in store.
Sky Blues pounded the Cookstown box with balls but Young was commanding and took control of many awkward situations, acting as sweeper on numerous occasions.
Wilson, Keane and Thom were resolute and it was their blocks that helped Dingley to find Larmour again in behind Sky Blues high line and again he slotted home very calmly.
Grimes came on to add something different to the attack and shortly after Arrell completed his hat trick after a well worked corner with a strike to be proud of.
Cookstown spurned many other chances but will be glad to get the win and most importantly progress to the next round where they take on Portadown at home.
Squad: Young, Thom, Keane, Wilson (c) Dobson, Kelly, Donnelly, Devlin, McMullan, Arrell, Larmour, Hughes, Dingley, Grimes