Drogheda United were full value for what was only their second league win of the season over high flying St Patricks.
United were the better side from pillar to post but left it late to snatch a winner in the 86th minute when Joe Kendrick sent a brilliant ball from the left wing into John Flood who drilled his shot past Gary Rogers.
Drogheda almost gifted Pats a lead goal early on when keeper Paul Skinner totally missed an attempted clearance but as the ball headed for the unguarded net with Vinny Faherty in hot pursuit Eoghan Osborne made the challenge that saved his teammates blushes.
Skinner redeemed himself a little later diving full length to his right to beat Ryan Guy's shot away.
However as the half progressed Drogheda took control and were full value for their lead goal that arrived with half an hour gone.
Indeed just before they scored Saints net minder Gary Rogers did really well to deny John Flood who capitalised on Conor Kenna's poor header back towards his colleague.
But there was to be no stopping Paul Crowley's bullet like header from Joe Kendrick's corner on the right that rattled the net.
United should have doubled their advantage seven minutes from the break after Flood centred a lovely ball to Gareth O'Connor who unfortunately guided his shot narrowly wide when another goal appeared certain.
The home side were then caught with a classic sucker punch in the second minute of additional time following the concession of a needless free by Alan McNally way out on the right which Derek Doyle floated into the box for Vinny Faherty who guided his header home.
In a lively enough second half clear cut chances were at a premium leaving Skinner with nothing to do and Rogers only having to deal with headed efforts from Flood and McNally that was until Drogheda struck for that late winner that dented the Inchicore outfit's title ambitions for the time being at least.