Fenstanton ensured the Sheeran Cup decider will be between two unbeaten champions elect.
The Senior Major Division front runners accounted for St Micheals in the semi final to set up a final with LFL Premier league leaders Tallaght City, who are also undefeated in league action this season.
Fenstanton started game quickly and where two goals to the good by half time. Brian Lawless opened the scoring before Sean Murphy doubled the lead before the break.
Micheals pulled one back after the turn around and pushed for a leveler. Fenstanton weathered the mini storm and put the result beyond doubt when Stephen Heeney restored the two goal cushion on 75 minutes.
Ten minuted later Gary Victory put the icing on the cake with his sides fourth.