Second half goals from Robert Dunne and Tony McDonnell saw Bohemians condemned to the Premier Division relegation play-off spot at Belfield yesterday.
Neither goalkeeper was seriously tested during a dreadful opening half but three minutes after the break the unmarked Dunne fired UCD in front from 14 yards.
In the 67 minute later McDonnell rose superbly to power home a header from Michael O'Byrne's corner.
Bohemians now face Cobh Ramblers in a two leg play-off if they are to secure their place in the top flight.
UCD: Ryan, Brett, McDonnell, Delaney, Mahon, McLoughlin, Kavanagh, Lynch, Dunne O'Byrne, Bennis.
Bohemians: Dempsey, O'Connor, Maher, Mullen, Brunton, Mooney, O'Hanlon, Hunt, T Byrne, Swan, Kelly. Subs: Lawlor for Swan (18 mins), P Byrne for T Byrne (53 mins), R Coombes for Brunton (70 mins).
Referee: J Stacey (Athlone).