Ireland Under-20 international Cathal Marsh kicked four penalties to guide Dublin University to 12-6 victory over Bruff at Kilballyowen Park.
Neither side could muster a try in a game played in a gale force wind with heavy rain. Cathal Marsh landed three successful kicks to give Trinity a 9-0 interval lead.
They went in front in the fourth minute after full-back David Fanagan did well to break out of his own half and reach the Bruff 10-metre line.
Marsh nailed his first kick at the posts and with busy openside Brian du Toit excelling at the breakdown, Trinity doubled their lead as Bruff were pinged for coming in at the side of a ruck.
Play swung back and forth with Bruff profiting from a well-oiled lineout and despite their early advantage, the visitors were unable to break into the Bruff 22.
Marsh's clinical striking with the boot was enough to establish a decent advantage for them, his third penalty success coming after Bruff were caught offside.
Bruff were by no means out of contention and they made a strong start to the second half. Centre Mark Cosgrove carried with purpose, drawing a penalty from Paddy Lavelle. Marsh's opposite number Brian Carroll did the necessary for 9-3.
The Limerick men were beginning to put some phases together in attack, but du Toit's influence at the breakdown was evident again as Bruff infringed and Marsh landed the resulting penalty to reopen the nine-point gap.
Trinity had to defend for much of the remainder and as Bruff dominated territory, they won a succession of penalties. Carroll fired over his second penalty as replacements Cathal O'Regan and Mike Carroll made an impact.
Mike Lynch's side hunted for an elusive try, their lineout maul was a dangerous weapon but they could not unlock the Trinity defence out wide when opportunities arose.
Both defences deserve credit for keeping their lines intact, with key men Ariel Robles, Jack Dilger and Alan MacDonald making sure Trinity kept their noses in front.
Despite showing huge commitments in all facets of play, Bruff had to settle for a losing bonus point and they remain eighth in the table ahead of next Friday's trip to Buccaneers.
Referee: Jonathan Peak (IRFU)