In a dramatic finish, the holders retained their title at Lansdowne Road after a last-gasp conversion attempt by Belvedere outhalf Robert Hedigan fell short of the target.
Belvedere started well, but Blackrock came back into it and almost scored through Andrew Geraghty five minutes before the break, but the scrumhalf spilled the ball just before touchdown. Rock breached the line soon afterwards when influential captain and centre David Nyhan sucked in the cover before offloading to Michael Kavanagh, who cut inside to score under the posts.
Geraghty converted but Rock's lead was short-lived. Belvedere back row Brian Kennedy charged down an attempted kick by Blackrock outhalf, David Cullen and then followed up to ground the ball. Hedigan added the two points to leave it all square at half-time.
Rock started brightly after the break, but penalty attempts by Kavanagh and Geraghty were missed. However, on 48 minutes, Cullen and Kavanagh combined to send right wing Chris Moore over into corner, and Kavanagh converted.
Belvedere pressed and were rewarded when Kevin Barden darted into the corner after starting a run from inside his own half. The difficult conversion kick was missed.
Belvedere College: K Barden (captain), M Mc Carthy, M Mc Allister, C Hayes, D Keane, R Hedigan, B Moran, G Brennan, R Carson, E Weigel, H Lacey, M Walsh, R Fitzgerald, R Mc Donald, B Kennedy. Replacements: H Mahon for Weigel (39 mins), R Armstrong for Mc Donald (58 mins), N Monahan for Carson (56 mins).
Blackrock College: M Kavanagh, C Moore, D Nyhan(Captain), D Barnett, N Madden, D Cullen, A Geraghty, G Walsh, C Culleton, S Creavin, R O'Hara, N Lysaght, G Flanagan, D Laffin, E O'Keefe.
Referee: D Woods (ARLB)