Holders, Crescent Comp, had this SEAT Munster Schools Senior Cup game wrapped up by half time at which stage they led 17-0.
It was a rare defeat of this proportion for CBC who will have to regroup to make progress.
Crescent led inside five minutes when second row Robbie Scott popped up on the wing and showed great speed to cross in the corner.
Cormac Blake had another try, converted by Fionn McGibney, and a delightful 1-2 between Calvin Nash and Scott saw the latter sprint in for a third try for his side.
Will Leonard, Jason O'Sullivan and Johnny Keane all had second half tries as Crescent remained totally in control.
McGibney added a penalty and replacement Dylan Sheehan converted Keane's try with the last of the action.
Second row Robbie Scott was outstanding for Crescent and Johnny Keane and Cormac Blake all shone in a dominant pack. Jack Harrington Will Leonard and scrumhalf Gary Fitzgerald sparkled behind.
For CBC it was a drubbing but it was not for want of trying and Alex Penney, son of Munster coach Rob, Evan Mintern and Jamie Murphy all did well.
Crescent College: J Harrington; J O'Sullivan, JJ O'Neill, W Leonard, C Nash; F McGibney, G Fitzgerald; M O'Donnell, C Moloney, L McMahon; R Scott, J Keane; S Fitzgerald, J Kavanagh, C Blake. Replacements: J Barry, M Rickard, M McGann, C Guerin, R Noone, E Barry, D Sheehan, B O'Hora (all used)
CBC: C O'Mahoney; T Tracey, M Clune, S McAuliffe, D Frufferty; J Murphy, R Cassidy; C Fitzgerald, V O'Brien, S O'Hanlon; E Mintern, C Barry; D Lynch, D Walsh, A Penney. Replacements: E Scully, R O'Donovan, C Leahy, G Stokes, L McSharry, S Kennedy, O McSweeney, B O'Callaghan.
Referee K Imbusch (MAR).
PBC 8, St Munchin's College 8. (by Leonard Allen)
St Munchin's College have earned themselves a home tie in the quarter finals of the SEAT Munster Schools Senior Cup after they were declared the winners of their first round tie against PBC at Musgrave Park on the first try rule.
John Poland broke the deadlock for the Mardyke College when he slotted over a penalty from outside the St Munchin's 22 midway through the opening half. Two minutes later he came close to doubling his side's advantage with a penalty, but his shot rebounded off the upright.
Alan Wallace equalized for the Limerick College with penalty from the Pres' 22, seven minutes before the break.
Shane Halpin put 'Munchin's in front when he capitalized on sloppy defending by Pres' to score a try in the corner. Wallace's conversion from an awkward angle rebounded off the post.
The Limerick side had Pres' pinned back entering the final quarter and they missed two opportunities of stretching their lead. The first occasion was when Wallace's third penalty attempt fell short of the posts and then Bobby Price's drop at goal was off target.
Pres' rallied to rescue the game in the closing stages and a try in the corner by Cian Collins levelled the scores but Poland's conversion attempt drifted across the face of the posts.
The Mardyke College continued to have 'Munchin's camped deep inside their own 22 with ten minutes of stoppage time played, but the Limerick side's defence held firm.
PBC: Rob Reardon; Darragh Dennehy, Paul Kiernan, Shane Daly, Cian Collins; Conor Flanagan, John Poland; Joe Ring, Cian Stanton, Steve MacCarthy; David Fitzgerald, Morgan Carey; Eoin Perry, Graham Smith, David St Ledger. Replacements: Jake O'Donovan, Conor Ormond, Emmet McCarthy, Caolan O'Flynn, Kevin O'Leary, Billy Pope, Robin Reidy, Luke Merriman, Conor Murphy.
St Munchin's College: Bobby Price; Mike Devaney, Edward O'Keeffe, Shane Halpin, Shane Doona; Alan Wallace, Brian Bennett; Peter Meyer, Luke O'Halloran, Brendan Keogh; David Begley, Nathan Nugent; Tom O'Dwyer, Ben Kilkenny, John Foley. Replacements: Corey Wells, Jordan Prendiville, James Burke, Steven Collins, Liam O'Dwyer, Adam Guerin, Josh O'Curry, Shane King.
Referee: Dave O'Flynn (MAR)
SEAT Munster Schools Senior Cup: Crescent College Comp. 39, C.B.C. 0;
P.B.C. 8, St. Munchin's 8 (Munchin's win first try rule)
Mungret Cup Semi Final: Bandon Grammar 20, St. Clement's 7;