UCD built on last week's display, against Shelbourne, to record their first competitive win of the season as they outplayed Sligo at Belfield.
Sligo offered little in attack without the injured Padraig Moran, while defensively they were poor.
Twice early on they were caught napping at the back from long throw-ins by Robert McAuley from which UCD should have scored.
His first on 13 minutes put Eoin Bennis in behind the Sligo defence up the left. Bennis did everything right, releasing the ball quickly inside to Mick O'Byrne. But O'Byrne, just back from a fortnight out with injury, scarcely troubled Matt Boswell with a weakly-hit shot.
Sligo hadn't heeded the warning, though, and again a long throw from McAuley put Bennis in. Thankfully for Nicky Reid's side, Bennis toe-poked wide. Sligo threatened briefly when Marcus Hallows lobbed over the top having played a one-two with Aled Rowlands, but that amounted to the sum of their efforts on goal in the whole match.
UCD were much the better side and the football improved as the half wore on. Robert Dunne shot feebly at Boswell and then shot wide when well placed, before UCD were rewarded with the lead goal on 34 minutes.
Aidan Lynch, the students' captain, beat Boswell at his near post with a rising shot from an acute angle.
UCD easily punished them again three minutes before halftime. Dunne gleefully drilled home his first league goal from 14 yards.
UCD: Ryan; McDonnell, Mahon, Delaney; McLoughlin, Kavanagh, Lynch, Dunne, McAuley; O'Byrne, Bennis. Subs: Kilmurray for Bennis (90 mins).
Sligo Rovers: Boswell; Callaghan, Hare, Sheridan, Lynch; Jones, O'Grady, Reid, Ogden; Hallows, Rowlands. Subs: Flannery and Hutchinson for O'Grady and Lynch (both half-time), Shannon for Hallows (74 mins).
Referee: R O'Hanlon (Waterford).