Second half strikes from Mark O'Sullivan and substitute Ross Gaynor saw Cork City take all the points from the Showgrounds on Micky Adams' first outing as Rovers manager.
Rovers had the better of the first half opportunities but were unable to break the deadlock. Morten Nielsen's chip to the back post was headed straight at Mark McNulty by Raffaele Cretaro with 15 minutes played.
The evening saw Jason Hughes make his Showgrounds debut and his vicious drive was claimed by City keeper McNulty on the second attempt, ten minutes from the break.
Cork's Karl Sheppard went close on two occasions during the opening period.
The away side took the lead on 58. Gavin Peers upended former Rovers full back Gaynor at the edge of the area. Brush did well to get a hand to O'Sullivan's shot from the resulting free but could only watch on as the ball found the bottom corner of his net.
Raffaele Cretaro headed over with five minutes remaining as Rovers piled on the pressure.
But it wasn't to be and Gaynor swept home with two to go after Brush blocked Steven Beattie's initial effort.
Sligo Rovers: Richard Brush; Alan Keane, Gavin Peers, Tim Clancy, Regan Donelon; Sander Puri (for Gary Armstrong 71), Jason Hughes, Gary Boylan, Raffaele Cretaro; Morten Nielsen, Dinny Corcoran (for Ruairi Keating 71).
Cork City: Mart McNulty; Colin Healy, Alan Bennett, Dan Murray, Kevin O'Connor (for Ross Gaynor 55); Steven Beattie (for Danny Morrisey 90+1), Liam Miller (for Stephen Folan 90+1), Johnny Dunleavy, Garry Buckley; Mark O'Sullivan; Karl Sheppard.
Referee: Paul Tuite.
Listen to Micky Adams post-match interview below: