AN opportunist try four minutes from full-time by influential scrum-half Brian Haugh sent Rockwell College into the last four at Clanwilliam Park.
Favourites Rockwell were made battle all the way by a plucky Ardscoil Ris before finally securing a meeting with CBC.
Ardscoil Ris led 3-0 at the break -- out-half Rory Collins kicking his side in front in the third minute.
Rockwell drew level three minutes into the second half when Haugh landed a penalty goal.
As the second half wore on, though, Ardscoil grew in confidence and sensed a possible upset, but they were unable to convert decent position into scores.
With extra-time looming, Rockwell forced a scrum inside their opponents' '22' and Haugh sniped over for the match-winning score.
ROCKWELL COLLEGE -- D McGillycuddy; S Horgan, H McNulty, K Kiely, R Jermyn; D Johnston, B Haugh; C O'Donnell (capt), D Mulcahy, MJ Murphy (E Phelan 58); A Sweeney (B Crosse 63), A O'Sullivan; R Moran, S Dwyer, L Cahill.
ARDSCOIL RIS -- J McGarry; K Phelan, A McNamara, A O'Byrne, E Farrell (S Considine 42); R Collins, S Noonan (C McLoughlin 42); D Canny, G Doherty, B Masterson; C Power, E McCabe; K Walsh, P Hodnett, P McGann.
REF-- O Hodges (MAR).