Simon Mitchell had touched down to give Tony Smeeth's men a deserving seven-point lead five minutes into the second half, but Indian winger Ajay Subherwal's second try on 65 minutes, ended Trinity's Stevenson Park trip on a sombre note.
The third-from-bottom students do however, have a quick chance to release their frustrations as they welcome Cork Constitution to College Park in a twice re-fixed tie.
A win for Smeeth's charges - by the smallest of margins - would move them level with eighth-placed Buccaneers, and temporarily out of the relegation mire with fixtures against fellow strugglers County Carlow and Lansdowne to come in the next fortnight.
AIB League fixtures: Saturday, April 2 (2.30pm unless stated)
De La Salle Palmerston v Highfield, Kilternan, 2.00pm
Wanderers v Old Wesley, Lansdowne Road back pitch, 2.00pmBallina v Banbridge, Heffernan Park