Half time finished up 3 a-piece with successful penalty kicks from Rockwell's Rory Parata and Munchin's Shane Airey.
Nine minutes into the second half Rockwell went ahead 6-3 following a well struck penalty, but Munchin's shared the spoils two minutes later when Airey was on target with his second.
Both sides gave it their all into the closing stages and with a replay looming, Rockwell were able to turn a solid phase of possession into a converted try bringing the final score to 13-6 in favour of the reigning champions.
Rockwell College: Steve McMahon; David O'Mahony, Shaun O'Donoghue, Rory Parata, William Coffey; Aidan Moynihan, Ben Riley; Denis O'Connell, Sean McNulty, James Maxwell; Neville Flynn, Sean O'Connor; Jimmy Feehan, Sonny Dwyer, Aidan Butler (capt). Replacements: Jack Bolger, David O'Dwyer, Luke Hickey, Adam Horgan, Tommy Anglim, Rory Horgan, Elliot Mulcahy, Alan McMahon.
St. Munchin's: Shane Halpin; Edward O'Keeffe, Dan Goggin, Dylan Kelly, Gary Bateman; Shane Airey, Ryan Meagher; David Begley, Peter Meyer, Brendan Keogh; Shane O'Mullan, Tom O'Dwyer; Killian Browne, Lee Nicholas (capt), Ben Kilkenny. Replacements: Thomas Madden, Eoghan Brennan, Jordan Prendeville, John Sheehan, Nathan Nugent, Alan Wallace, Shane Doona, Kelton Faloon.
Referee: O Hodges (M.A.R.)