Waterford Utd - 0 Shelbourne - 1: League leaders chasing a title are always wary of visiting a bottom-of-the-table club and the RSC cauldron was always going to be a difficult fixture for ambitious Shelbourne.
But the Reds dug deep against a gritty and determined Waterford United and overcame a decidedly shaky start to take all three points and stay on course for the crown.
The Blues held the visitors scoreless to the break but Shelbourne moved up several gears on the resumption and it soon became apparent that it was only a matter of time before the brave United defence was unhinged.
Shelbourne finally broke the deadlock from the penalty spot 17 minutes into the second half when Paul McCarthy, one of the Blues' best players on the night, took down the inrushing Ollie Cahill. Stuart Byrne was clinical in his conversion.
Prior to the goal, the league leaders subjected United to a fierce onslaught forcing a succession of corners that were somehow scrambled away.
On three notable occasions, Cahill ran into open space in front of goal but his colleagues failed to deliver the killer ball.
The first 22 minutes were entirely forgettable as untidy, scrappy play swung from end to end without either goalkeeper being troubled.
Shelbourne finally clicked into gear when Colin Hawkins played a measured through ball down the right wing for Gary O'Neill. The former Blues favourite timed his run perfectly to beat the offside trap before sending over an enticing cross for the in-rushing Stuart Byrne.
However, goalkeeper Ben Spicer raced off his line and punched the ball clear off Byrne's head. Three minutes later, a free by Joseph Ndo found Glen Crowe but he headed straight at the goalkeeper from eight yards.
Shelbourne almost opened their account on 34 minutes after Pat Flynn conceded a corner to the left of goal. Ndo took the kick and Seán Dillon's powerful volley came back off the upright before Bobby Ryan ballooned the rebound wide.
Three minutes before the break, United almost took the lead against the run of play. AlanReynolds found McCarthy and his dipping, 30-yard screamer shaved the top of the crossbar. On a night when their closest rivals slipped up, it was a significant win for Pat Fenlon's men.
WATERFORD UNITED: Spicer; Flynn, Hedderman, Keely, Browne; Reynolds (Pender, 87 mins), Grant (McDonald, 65 mins), McCarthy, Brosnan; Hayes, Kavanagh.
SHELBOURNE: Williams; O'Halloran, Dillon, Harris, Hawkins; Ryan (Baker, 85 mins), Cahill, S. Byrne, Crowe; O'Neill (J. Byrne, 59 mins), Ndo (Crawford 88 mins). Subs not used: Moore, Delaney.
Referee: P Whelan (Dublin).
