Clontarf ran out convincing 235-run winners over The Hills in a surprisingly one-sided affair at Sydney Parade.
Having been put in, Clontarf openers Eoghan Delany and Ryan Karunakaran made their opponents regret that decision as they plundered an opening stand of 204 in 35.2 overs to all but settle the decider.
Ireland Academy player Karunakaran hasn't been at his best since his delayed arrival at Castle Avenue, but came good on the big occasion as he top-scored with 105 from 109 balls (12 fours, two 6's), while skipper Delany's 88 from 107 balls included seven boundaries.
That laid the platform for PJ Moor to clear the ropes five time in a rapid 47 from only 25 deliveries, while David Delany's quickfire 44 saw Clontarf finish on 343 for 7 - three wickets for Nicolaj Laegssgaard and two for Cian Nulty.
Fionn Hand then celebrated his recall to the Irish senior ranks by taking five wickets in a Man of the Match display as The Hills slumped to 37 for 6.
There was no way back, although Nathan Rooney (26) and Cian Nulty (23) got them up to 108.