The Armagh side dominated the second-half, hitting 16 points without reply.
St Paul’s, who only switched from playing Vocational Schools football four years ago, started brightly with three points inside the opening nine minutes from Conor Sloan (two) and captain Michael Murphy.
However, Ardscoil hit back with a goal from full-forward Greg Murphy in the 10th minute and led 1-3 to 0-4 at half-time.
However it was all one-way traffic in the second-half as St Paul’s piled on the points.
Scorers for St Paul’s: C Sloan (2fs), C O’Hanlon (2fs) 0-5 each, C Mackin, J Hall, C Nugent 0-2 each, M Murphy, C McCullagh, G McCabe, A Nugent 0-1 each.
Scorers for Ardscoil Rís: G Murphy 1-0, S Heaney, G Burke, S Barrett 0-1 each.
ST PAUL’S: B Hughes; C McCooey, C Moley, S Lavelle, F Burns; P Campbell, A McKay, E Burns; M Murphy, C Mackin; C Sloan, G McCabe, C McCullough; C O’Hanlon, R McCabe.
Subs: C Nugent for McCabe (ht), J Hall for McCullough (45), P Hughes for Mackin (56), J Cosgrove for Lavelle (58).
ARDSCOIL RÍS: L Carey; C Burke, S Ruane, C Mullins; S O’Keeffe, J Collins, L Casserly; C Costello, S Heaney; C Dolan, G Burke, S O’Meara; S Barrett, G Murphy, A Baxter.
Subs: D Smith for Dolan (37), J Kirrane for Murphy (45).
Referee: F Kelly (Longford)