First half tries from Barry Daly and Andrew Boyle set UCD up for a deserved Colours victory over Dublin University at Belfield. With Ulster Bank League points also on the line, the result has moved UCD into second place in the Division 1B table.
Former Ireland Under-20 international Barry Daly had a considerable influence for the victors, with his eighth try of the league campaign being the springboard for UCD's fourth win on the trot.
When these rivals last met at College Park in November Trinity ran out decisive 36-14 winners, but UCD, especially on their home patch, were never going to allow for a repeat.
UCD made initial headway in front of a bumper crowd. Out-half James Thornton tried his luck with a drop goal effort from close range which missed the uprights.
Thornton's opposite number David Joyce missed a penalty before Trinity opened the scoring in the 12th minute. They turned over a UCD scrum with number 8 Jack Dilger securing possession and a quick feed from Joyce put centre Ciaran Wade over unopposed for the first try.
Joyce tagged on the conversion, however the visitors were under pressure from the restart as UCD energetically chipped away at Trinity's well-organised defence.
They held them at bay until a spell towards the end of the first quarter. A missed penalty from Thornton was followed immediately by Daly's 21st-minute try, as the winger straightened and swept away from four defenders on his way to the line.
Daly was one of UCD's marked men but he took full advantage to expose some sloppy defending from Tony Smeeth's side. Thornton converted to bring the home side level.
UCD pressed again soon after, Thornton missing a penalty before he knocked a subsequent penalty into touch. Trinity centre Paddy Lavelle gobbled up a loose ball to relieve the pressure on his side but UCD were beginning to tighten their grip on proceedings.
Daly, using his power and pace once more, broke off the base of a ruck to sidestep the first defender and break the defensive line. He looped an excellent pass away to supporting full-back Andrew Boyle whose angled run saw him score in the corner under pressure from the speedy Niyi Adeolokun.
Thornton's conversion was followed by a late rally from Trinity at the end of an eventful and free-flowing first 40 minutes.
The Trinity backs threatened in the UCD 22 with Neil Hanratty probing out wide, he linked with Lavelle but the busy centre lost the ball into touch just as an opening appeared.
The pace slackened in the third quarter with defences on top and the scoreline remaining 14-7. Thornton struck the crossbar with a penalty attempt and had a second miss in the 49th minute.
Both sides played with plenty of width and wingers Sam Coghlan Murray and Adeolokun got involved as often as possible, dashing upfield on kick chases and getting stuck in at the breakdown when the opportunity arose.
Cathal Marsh, another of the Ireland Under-20-capped contingent on show, came off the replacements bench to kick a 61st minute penalty for Trinity.
Man-of-the-match Daly was heavily involved again with some clever offloads out of the tackle, and a fine piece of fielding from centre Alex Kelly, who gathered a garryowen from replacement Niall Earls, inspired a crucial series of drives from the forwards.
UCD muscled their way back into the Trinity 22 and drew a penalty which Earls did well to slot from a left-sided position, putting seven points between the sides.
There was still five minutes left in this Friday Night Lights encounter, but despite the best efforts of Marsh and company the losing bonus point was their only reward.
As well as keeping the Colours trophy in UCD hands, the result has moved Bobby Byrne's youngsters into second position in the Division 1B standings – they are level on 39 points with third-placed Trinity, but are higher ranked due to their superior points scoring difference.
Referee: Paul Haycock (IRFU)