Brave CBC Monkstown could not quite manage to spring a surprise in this superb encounter at Donnybrook yesterday.
It all went to plan for 'Rock early on, their continuity stretching CBC to breaking point for centre Joe O'Hehir to reach for a touch down in the seventh minute.
However, Leinster League finalists Monkstown brought a tidy pre-Cup record and a willingness to move the ball at every opportunity, and they hit back when centre Sean Smyth made the hard yards for his out-half Sean Kearns to put wing Joseph Halwax in at the left corner.
It got even better for CBC when Kearns reversed into the pocket to snap over a textbook drop goal on the stroke half-time for an 8-5 interval lead.
The game was in the balance, so the next score was to prove crucial. 'Rock took the initiative and immediately went on the attack for lock David O'Connor to drive over. Dillon Coughlan's conversion went over off the upright.
The four-point gap was turned into a two-score lead when excellent scrum-half replacement Tristan Brady chipped over the top for right wing Johnny Redmond to come off his right foot for a well-taken try that sealed the result.
Blackrock College --Z O'Hagan; J Redmond, J O'Hehir, I Kinsley (G Glynn 66), D Coughlan (D O'Mahony 69); J Power, S Colgan (T Brady 37); S Lynch (H Kean 69), G Moylan (D Fitzpatrick 69), E Holland; J Dwan, D O'Connor; J Moore (O Jager 56), E Fanning, N Timoney (capt).
CBC Monkstown -- C Cullinane; K Wolfe, M Courtney (capt), S Smyth, J Halwax (S O'Donnell 57); S Kearns, B Mahon (J Toale 57); G Byrne (M Hallam 57), C Cunningham, K Patterson; J O'Connor, C McDonald; B Keavney (C McGovern 69), D Haney, J McGrath.
REF -- A Lynch (Leinster Branch).