Barry O’Mahony was in inspirational form at Anglesea Road as Clontarf climbed to the top of the Division 1A table with a hard-earned victory over bottom side Old Belvedere.
Old Belvedere, who parted company with head coach Phil Werahiko last week, are still without a win in this season's Ulster Bank League and now have a major task in the quest to avoid relegation from the top flight.
The visitors made a bright start to the proceedings, which also doubled up as the Jack Whelan Binsey Cup, as they aimed to attack the heart of the 'Belvo defence from the word go.
The reigning champions did handle this early pressure quite well though, and they started to gain more possession in the 'Tarf half after the opening few minutes.
There were precious few chances in a scrappy opening, but it was the hosts who eventually took the lead ten minutes in, as winger Eamonn Fitzgerald, a nephew of former Ireland captain Ciaran Fitzgerald, split the posts from a 25-metre penalty – much to the delight of the onlooking home support.
Indeed, 'Belvo were the dominant side in terms of territorial play during the opening 20 minutes, as they were putting Andy Wood's charges on the back foot at every opportunity.
However, they were finding it hard to create any meaningful try-scoring opportunities and when Clontarf started to settle into the game again, they were powerless to stop number 8 Frank Cogan bursting through for the first try of the game, following excellent approach play by captain Barry O'Mahony.
Full-back Richie Lane was on hand to convert this score, and this was added to by a second try from centre Killian Lett in first half stoppage time, giving Clontarf a 12-3 interval advantage.
Nine points was a far from insurmountable deficit for the Ballsbridge outfit to be facing into, but Clontarf increased their advantage to 15 points just nine minutes after the restart with a brace of penalties from tight angles by the ever reliable Lane.
The game was starting to slip away from 'Belvo at this stage, but a moment of magic from full-back Daniel Riordan set up Eddie Devitt – the Old Belvedere hero in last year's semi-final triumph over the same side – for a try in the right corner after 54 minutes.
This did offer 'Belvo a glimmer of hope, but the superb O'Mahony put paid to any potential comeback with a superb breakaway try with nine minutes remaining, converted by Lane.
'Belvo battled admirably until the finish and registered an injury-time try for replacement Michael Oyuga, but it was not enough to deny Clontarf a vital four points on the day.
Referee: John Carvill (IRFU)