Clontarf took an early lead with a penalty from Daire O'Shea, but Leinster's new back, Paddy Wallace, soon levelled the scores.
'Tarf came back when a charging run from Leinster lock Ben Gissing saw him off-load to O'Shea, who touched down for the first try of the game. However, Wallace kept his side in touch with another penalty, to leave it 10-6 at the break.
The second half opened with a period of dominance from Ballymena which was duly rewarded when Ulster's Adam Larkin crashed over. Wallace, who had set up Larkin, then converted to give his side a 10-13 lead. Larkin wasn't done yet and within minutes he clinched his second, which Wallace also converted.
Despite another penalty from O'Shea, the game looked all but over when a great individual try from Jimmy Topping gave teh Ulster side a 13-25 lead.
However, it wasn't over just yet, as Clontarf then began a comeback. Ollie Winchester went over for 'Tarf's second try, but when flanker Dave Moore's touchdown minutes later was hailed as a double move by the ref, Clontarf were left dejected and running out of time. They kept the attack up for the remaining few minutes, but a late drop goal from Adam Larkin sealed their fate and Ballymena were champions.
The Ulster side had eight contracted players in their side to Clontarf's two and that was effectively what split the sides today.
Clontarf: D Hewitt, N O'Brien, D O'Shea, J Downey, O Winchester; A Dunne, R O'Reilly; W O'Kelly, B Jackman, A Clarke, B Gissing, A Wood, D Quinn, D Moore, S O'Donnell.
Reps: J Wickham, A Cullen, G Flynn, C Power, R O'Reilly, D Higgins, D McElligott.
Ballymena: P Wallace, J Topping, M Waterhouse, H Jones, S Young, A Larkin, P Spence; S McConnell, P Shields, B Young, M Blair, G Longwell, M McCullough, R Nelson, N McMillen.
Reps: I Campbell, N McKernan, D O'Kane, A Graham, A Monson, A Maxwell, D Topping.