Shelbourne - 1 Longford Town - 0: Jason Byrne's 100th league goal, his 50th for Shelbourne, maintained the champions' revival to move them to within three points of leaders Cork City.
This win, Shelbourne's third on the spin, was, however, cruel on a Longford side that truly deserved something from a match they had the better of.
Ironically for Longford, whose defence hadn't conceded a goal in their previous seven games, a mistake cost them the match.
Barry Ferguson was caught in possession three minutes after the break. Joseph Ndo got on the ball to put it through to Byrne who spun one way then the other before drilling a left-foot shot past Stephen O'Brien.
If Byrne got their match winner, goalkeeper Dean Delaney, voted man-of-the-match, was Shelbourne's saviour with key saves.
Perhaps Delaney's most crucial contribution came on 57 minutes when he stood his ground well one-on-one with Paul Keegan to prevent what looked a certain equaliser.
Longford were the better side for good spells, with former Shelbourne players Davy Byrne and Dean Fitzgerald winning the midfield battle. There was no way past Delaney, however, as the Dublin side put the heat on Cork.
SHELBOURNE: Delaney; Heary, Rogers, Crawley, Cahill; Baker, S Byrne, Ndo, Ryan; Crowe, J Byrne. Subs: Fitzpatrick for Crowe (72 mins), Hoolahan for Ndo (80 mins), Cawley for J Byrne (87 mins).
LONGFORD TOWN: O'Brien; O'Connor, Ferguson, Dillon, Paisley; Kirby, Byrne, Fitzgerald, Martin; Myler, Keegan. Subs: Baker for O'Connor (79 mins), Cronin for Martin (84 mins).
Referee: J Feighery (Dublin).