The Students scored in the 11th minute when referee Neil Doyle awarded a penalty against Gary Kelly and Dean Marshall sent Greg Fleming the wrong way.
United took just six minutes to get back on level terms, Alan Murphy turning Gary Curran’s shot home from three yards.
The visitors got their noses in front again in the 29th minute thanks to a howler from Fleming, who punched Meenan’s cross towards his own goal, with Graham Rusk getting the final touch and Rusk extended the visitors’ advantage five minutes later.
Bobby Ryan threw the home side a lifeline just before half-time, getting on the end of Karl Moore’s cross with a diving header. The visiting keeper kept his side in front with a string of top-drawer saves early in the second-half and, as United began to fade, substitute Cillian Morrisson restored UCD’s two goal advantage in the 78th minute.
Murphy getting his second from the penalty spot in the 82nd minute.
GALWAY UNITED: Fleming; Preston-Kelly, Maher, Walsh, Kelly; Ryan, Curran, Sinnott (Dusi 69), Moore; Murphy, Caldwell.
UCD: Barron; Nangle, Leahy, D O’Connor, Russell (Boyle 74); Marshall, P O’Connor, Corry (inj, Morrisson 57), Meenan; Rusk, Benson (Ledwith h-t).
Referee: Neil Doyle (Dublin).