Substitute Cillian Morrison bagged the insurance goal on 85 minutes as UCD took all three points from this Airtricity League Premier Division encounter at Thomond Park with a 3-1 win.
Only two minutes had elapsed when a Craig Curran penalty gave Limerick a perfect start, but UCD came swinging back as Martin Russell's side were level by the 26th minute courtesy of a smart finish from the impressive Dean Clarke.
UCD took the lead on 42 when David O'Connor appeared to get the last touch following a Samir Belhout corner.
Morrison scored late on and then Limerick had Shaun Kelly sent off for a challenge on Sean Russell in the 90th minute.
Limerick were quickly out of the traps as fine right wing work from Danny Galbraith disturbed UCD and referee Rob Rogers deemed that Gareth Mathews fouled Craig Curran in the area.
The Students' felt it was a controversial decision, but Craig Curran confidently tucked away the resultant penalty as Limerick hit the front.
Despite the early concession UCD rallied and didn't allow Limerick stitch any sustained passing patterns together.
That meant UCD were able to pose questions of the locals and Limerick defender Patrick Nzuzi had to be alert to deny Dean Clarke in the ninth minute.
Clarke was proving to be a willing frontrunner for UCD, though, and his enthusiasm was rewarded with a subtle 26th minute equaliser.
Buoyed up by Clarke's strike UCD were in the ascendancy and they scored again following Limerick confusion at a set piece.
Samir Belhout's corner wasn't adequately dealt with and David O'Connor appeared to supply the final touch as UCD edged ahead.
Chances were scarce during a tight third quarter which showcased the midfield promise of UCD duo Craig Walsh and Robbie Creevy.
Though Limerick are particularly strong in the centre of the park with Joe Gamble, Stephen Bradley, and David O'Leary proven performers UCD continued to be hearty and honest.
Morrison raced clear to filch a splendid goal with five minutes left and Kelly saw red in the closing seconds as UCD held out.
Limerick FC: Barry Ryan; Shaun Kelly, Patrick Nzuzi, Stephen Folan, Shane Costelloe; Joe Gamble (Rory Gaffney, 73), David O'Leary, Stephen Bradley; Danny Galbraith, Craig Curran, Axel Bossekota (Darragh Rainsford, 77).
Subs not used: Shane Cusack, Barry Sheedy, Carel Tiofack, Tony Whitehead, Colm Murphy.
UCD: Ger Barron; Gareth Mathews, Michael Leahy, Tomas Boyle, David O'Connor; Samir Belhout (Cillian Morrison, 75), Craig Walsh, Robbie Creevy, Sean Russell; Robbie Benson; Dean Clarke.
Subs not used: Mark McGinley, Hugh Douglas, Barry McCabe, Michael Kelly, Thomas O'Halloran, Gary Burke.
Referee: Rob Rogers (Dublin).