Michael O'Halloran held his nerve to slot a penalty five minutes from full-time and keep Christian Brothers College's hopes of retaining their title alive.
A draw was a fair result after a lively game in which the lead changed hands a few times at Clanwilliam Park.
Rockwell's Bill Johnston and O'Halloran exchanged penalties before flanker Daire Feeney got in for a try for CBC, which O'Halloran converted.
Johnston landed a second Rockwell penalty right at the end of the first half to reduce the gap to four points, 10-6, at the interval.
Rockwell went back in front five minutes into the second half when centre Liam Molloy touched down, with Johnston finding the target with the conversion.
However, O'Halloran made no mistake with his late kick to force a replay in Cork, probably next Monday.
Rockwell – S Quirke; C Manton, L Molloy, B Ryder, K Moynihan; B Johnston, D Egan; N Campion, B Murray, J Tierney; J Binchy, C Cashman; J Kennedy, D Fehilly, B McLoughlin. Reps: H Gilbert, C Beary, M Irwin, M Wilson, L Devereaux, K Looby, T Brennan, J Stone.
CBC – S Murphy; K O'Sullivan, A McHenry, O Conway, A O'Brien; M O'Halloran, R Maguire; G Moloney, F Hennessy, C Leahy; D Barry, D O'Donovan; D Feeney, E Cahill, D McGinn. Reps: E Barrett, J Humphries, R Hyde, C Penney, R Cassidy, T Mackessy, J Taylor, J Hodder.
Ref – C Harrington (MAR).