Having topped the table for virtually the entire campaign, Rugby Club's disastrous last four games has seen them beaten twice and held to a draw once, finally resulting in having the title snatched from them at the death.
Anthony Colquitt, Adam Cassidy and brother Darren Cassidy (pen) put Powerhouse 3-1 up at the break, David Gray replying, before two goals in the last ten minutes from Kris Fearnley and Darren Cassidy again from the spot, sealed the triumph.
Jarrad Harris (Powerhouse) and Paul Campion (Rugby Club) were sent off in a rousing decider.
Lewis Taylor was the hat-trick star in Prince Madoc's 4-2 win at Bee Hotel, who finish holding the wooden spoon after only managing two points from two draws all season. Bobby Gaze was Prince's other scorer with Andy Smith netting for the Bee to make it 2-1 midway through the first half.
Three players were red-carded as Royal Oak battled out a lively 4-4 draw with Magpie & Stump.
Andy Coren, Kevin Gorrey and Paul Jilge had the Oak ahead after James Crowe and Shaun Davies (pen) had fired Magpie level following an earlier penalty miss by Magpie's Dean Hughes. James Price increased the lead but Dean Hughes atoned for his penalty lapse with a third for Magpie who were rescued by James Crowe's late leveller.
League officials have welcomed an application to join the League next season from Golden Sands, Towyn, and are inviting any other interested clubs to come forward as they aim to build up the numbers.
This Sunday's fixtures are: Premier Cup (Quarter-finals): Leddens Transport v Prince Madoc; Magpie & Stump v Royal Oak; Powerhouse Gym v Bee Hotel (at Abergele).