Shamrock Rovers moved out of the relegation zone to record their first win in five games at Morton Stadium, Santry, yesterday.
Damien Richardson's side haven't beaten Cork since November 1996 but secured the points thanks to goals from Brian Byrne and Sean Francis.
For Cork City manager, Derek Mountfield, it was a lost opportunity to close the gap on Shelbourne but they can have no complaints about the result with Rovers by the far the better team.
Rovers were very incisive early on and within the first four minutes could have been two goals up.
Both chances fell to Tony Grant, the striker' s first effort clearing the crossbar, the second a few moments later skimming the top of the woodwork.
City who were just four points off the lead at the start of the day were afforded few opportunities in the opening stages but after 12 minutes Colm O'Brien shot to force a corner.
But with the home side controlling matters it came as no surprise when they took the lead on 23 minutes when Marc Kenny floated in a fine ball from the right. And up popped an unmarked Byrne to head into the roof of the net with keeper Noel Mooney given no chance.
Eight minutes later, however, the two sides were level when Waterford referee, Jimmy O'Neill spotted an infringement in the Rovers penalty area following a free from Steve Gaughan and Pat Morley duly tucked away the resultant spot kick.
But Rovers pressed on and Thomas Dunne sent over a cross from a short corner and Byrne was again on hand to head home in stoppage time at the end of the first half.
And the game then ended as a contest when Francis raced onto a ball from Kenny and curled his shot beyond Mooney with just two minutes gone in the second half.
Francis proved equally adept with his finishing with five minutes remaining when he rolled the ball home after an incisive through ball from Derek Tracey.
Shamrock Rovers: Horgan; Smith, Palmer, Cronin, Dunne; Kenny, Colwell, Tracey, Byrne; Francis, Grant. Sub: Robinson for Grant 87 mins.
Cork City: Mooney; Horgan, Napier, Daly, Delaney; O'Brien, Gaughan, O'Halloran, Cahill; Mulligan, Morley. Subs; Caufield for Cahill 57 mins, Herrick for O Halloran 57 mins, Coughlan for Mulligan 78 mins.
Referee: J O'Neill (Waterford).