Castleknock were 15 points clear at the break following tries from Conor Barry, Dan O’Connor, and a penalty and conversion from Brian Collins.
On the restart, centre Shane Kelly nailed a drop goal, before O’Connor and McKeon completed the rout.
: Castleknock College: D O’Connor 2 tries; C Barry, B McKeon try each; B Collins pen, 2 cons; S Kelly dr gl.
: N O’Donoghue; B McKeon, S Kelly, R Greally, D Steacy; B Collins (capt), D O’Connor; R Murphy, C Barry, E Boylan, D O’Riordan, D McDonald, M Sheerin, E Cummins, T Walsh.
: A Redmond for McDonald 61 mins; T Delaney for Steacy 64 mins.
: C Spillane; D Finnegan, R Kohls, G Foley, S Stephens; J McGann, A Quinn; J Cullinan, B Clarke, D Steyaert, R Fayne, D Kennedy, C Raghallaigh, S Grannell, P Grannell (capt).
: P Whelan for McGann 49 mins; S Boucher for Grannell 57 mins; E McCarthy for Clarke 63 mins.
: A Rogan, Leinster Branch.