Roscrea started their game with Monkstown at Castle Avenue with six players that featured in last year’s final defeat to Belvedere College, and they took a deserved lead in the 24th-minute.
Impressive centre Adi Donavan raced over after spotting a gap inside the Monkstown ’22’, and this score was followed by a Tadhg Bird conversion. A second try from Finbarr Crowley followed, ensuring Roscrea held a 12-0 cushion at the midway point.
Pieter Swanepoel’s charges looked primed for victory, but Monkstown got their account up and running with a close-range Reynolds place-kick three minutes after the restart.
Roscrea continued to pose an attacking threat as the half wore on, but thanks to another routine three-pointer by the reliable Reynolds, Monkstown cut the deficit to six with 12 minutes remaining.
However, with tighthead prop Michael Milne in outstanding form, Roscrea claimed a hard-earned 12-6 triumph.
They will now face Gonzaga in the last-eight after the Ranelagh school secured a 14-10 win over Castleknock at a rain-soaked Donnybrook.
Eight-time winners Castleknock had opened the scoring with a ninth-minute Cian Egenton penalty, but after Gonzaga gained a foothold from the restart, Sean Galvin crossed over via an excellent James Kenny offload.
Gonzaga enhanced their advantage when Galvin was once again on hand to finish off a fine move, and thanks to Michael O’Kennedy’s second successful conversion, they established a 14-3 interval cushion.
Gonzaga now looked odds-on to progress, but Castleknock eventually reduced the gap at the rain-soaked south Dublin venue.
With Gonzaga’s Ian O’Grady in the sin-bin, Castleknock made their temporary numerical advantage count — as Darragh McNally touched down underneath the posts. A routine Donncha Ryan conversion meant only four points separated the sides, but in spite of their best efforts, Gonzaga ultimately prevailed.
Elsewhere in the quarter-final draw, defending champions Belvedere College were paired with St Michael’s College, while Blackrock College and Clongowes Wood College will play Terenure College and St Mary’s College respectively.
T Bird; B Hyland, P O’Shea, A Donavan, P Keane; C Kelly (captain), F Crowley; J Wycherley, T Byrne, M Milne; R Lomas, N Moylett; C Walsh, R En-Moony.
J Cahir, L Rigney, D Maher, L Culleton, J Corcoran, L Crowley, B Murphy, J Culleton.
J Reynolds; C Newman, C Watson, D Forster, L Sweeney; S Power, S O’Hanrahan; M Read, M Theunissen, C Kavanagh; R Ivers, E Vaughan; R Doyle, Z Sattar, E Clarke (captain).
K Kouadri, G Tinney, J Browne, L Hallam, C Byrne, H Shaw, C Tallon, G Mahon.
Belvedere College v St Michael’s College; Blackrock College v Terenure College; Cistercian College Roscrea v Gonzaga College; Clongowes Wood College v St Mary’s College.