Sligo Rovers 0 Cork City 1
Sean Kelly's first goal of the season earned Cork a vital win to set up a showdown with Bohemians to decide third place at Turner's Cross next Friday night.
City are now level on points with Bohs, but as the Gypsies have a better goal difference, the Leesiders must beat them to get the InterToto Cup slot at least - with the cup final against Longford Town to come.
The only goal of a lively game came on 69 minutes when Sligo failed to clear Leon McSweeney's corner and defender Kelly nodded home form six yards.
James Meredith came closest to equalising on 81 minutes when working a one-two with Matt Judge, but Michael Devine made a good stop.
Judge fluffed Rovers' two best openings in the first half, lobbing over the bar on eight minutes before heading tamely into the arms of Devine minutes later.
But it was Rovers' keeper Tomislav Arcaba who had to make the best save of the night on 24 minutes, diving full stretch to push out Gareth Farrelly's stinging drive from 25 yards.