JOE D'ARCY's late try settled an absolutely riveting game at Donnybrook as Newbridge squeezed into the semi-finals.
In the end, the more rounded unit, playing the more adventurous rugby, edged home, but it could so easily have gone either way.
Neither school left anything behind.
CBC warmed to the occasion the quicker and for the opening quarter dominated position and possession.
However, all they had to show for their superiority was a second-minute Ben Mahon penalty.
Skipper and No 8 Mark O'Mahoney led the way, ably supported by openside flanker Andrew Brennan.
A Chris Healy penalty levelled it up on 17 minutes before a powerful burst by Adam Swan culminated in a brilliant individual try for the strong-running CBC centre.
It made for an 8-3 lead to the Monkstown school at the break – probably just about right on the balance of play.
But whatever was said by Newbridge coach Aaron Dundon at the interval, it had the desired effect.
From the restart Newbridge camped in CBC territory and up until the hour mark refused to shift.
Healy added a second penalty in the 37th minute before quicksilver winger D'Arcy crossed in the corner for a fine try, engineered by Tom Brady, Mark Sutton and Healy.
That gave Newbridge a fully deserved 11-8 lead.
But some sterling work by Joshua Brown, Brennan and Eoghan McKeever, when CBC eventually made it into the Newbridge half, paved the way for Mahon to bring the sides level again by way of a second penalty in the 63rd minute.
From then to the end it was nip and tuck.
However, Newbridge – with stand-out performers in Brady, Oisin McKnight (as influential a flanker as has appeared in the competition to date), Cormac Nugent, D'Arcy, Sutton and Healy – eventually carved out the winning try their second-half dominance warranted.
It came in injury time when yet another inspirational Sutton pass found Niall Delahunt over from the right on the drift in the attacking line.
Delahunt timed his pass to perfection for ace poacher D'Arcy to cross for his second try and the match-winning score.
Agony for CBC and ecstasy for Newbridge followed, but it made for the right result at the end of an absorbing encounter that did both schools proud.
NEWBRIDGE – C Healy; N Delahunt, P Kyne (J Howlett 45), J O'Neill (A Shanahan 64), J D'Arcy; M Sutton, J Coghlan-Murray (R Mullen 52); J Phelan (E Wynne 58), C Doyle, H O'Donnell; C Nugent, B Hayden (capt); M O'Connor (R Drumgoole-Maguire 64), O McKnight, T Brady.
CBC – M Halwax; H Godson-Treacy, M Courtney, A Swan, S Smyth; C Cullinane, B Mahon; K Patterson, D Hanney, E McKeever; B Keaveney (V Laws 40), J McGrath; J Brown, A Brennan, M O'Mahoney (capt).
REF – D Phillips (LRR)