Two struggling sides met by the Camac and the first goal was always going to be critical, with Ali Coote's helping Shelbourne to all three points in the SSE Airtricity Premier Division encounter at Richmond Park.
Coote's early strike had a touch of fortune about it and Shels offered next to nothing thereafter but held on grimly against a Pat's side that was far too slow to get going and is evidently in something of a mid-season slump.
Key players for both of these well-backed teams are not performing as envisaged but Shels still know how to battle and, though they rode their luck, they were able to hold out. The mood in Inchicore has been better and boss Stephen Kenny has much about which to ruminate.
Shels now join Pat's on 30 points, but that is from a possible 63, with neither of these looking anywhere near title contenders at the moment. For now, Damien Duff can enjoy that feeling of winning a Dublin derby again.
On a beautiful night for a ball game, there was plenty at stake. An attendance of 4,421 was well short of a sell-out, which again reflects that both of these sides have faltered since reasonably good starts to the campaign.
Mason Melia and Zach Elbouzedi both dropped to the bench for the Saints; Shels' five changes reflected both their busy schedule and their own struggles of late.
Coote could have been in on seven minutes but referee Paul Norton had already blown his whistle for a free.
Coote would not be denied after 10 minutes.
Typical of the passive Pat's first-half offering, Mark Coyle was allowed to run far too easily towards the box and, after Evan Caffrey's cross, Tyreke Wilson squared to Coote, whose effort was deflected home by Tom Grivosti.
Saints were over a year unbeaten in the league in Inchicore but they were poor in the opening half, lacking belief and making simple mistakes. Finally, they worked something midway through the first 45 and, after Kian Leavy miscontrolled, Jay McClelland's effort was blocked.
Shortly afterwards, Anto Breslin's inability to control a regular pass, Jamie Lennon doing the same moments later, summed up the Saints' offering.
Paddy Barrett was far too casual under a high Joe Redmond ball on 27 minutes and Saints forced another corner, from which the ball was deflected for another. It came to nothing.
Caffrey's clip found Seán Boyd free in the box but it was not easy to cushion the ball and Boyd's first-time effort reflected the pace on the pass. He then saw yellow for a strong challenge on Ryan McLaughlin, though he appeared to win the ball.
A triple interval substitution for Pat's showed where they were at. Jake Mulraney barely touched the ball in the first half and had no chance of doing so in the second, while Breslin and McLaughlin were also substituted at the break.
Mason Melia's impact was almost immediate, as he was bundled over by Sam Bone a minute in, with Shels now sitting back and inviting Pat's on. Barrett pulled Aidan Keena back inside the box eight minutes after the restart but, perhaps tellingly, the Saints' crowd's protests were far more vigorous than the players'.
Bone was struggling with Melia and the home fans were roaring for a red card when he clipped him on 63 minutes, with Norton making what looked the right call to give yellow, a let-off for a Shels side who had no offensive threat at this stage
Simon Power's pace was rarely seen but he did well on 72 minutes and squared to cause mayhem in the box, with Elbouzedi, seconds on the pitch, having his shot blocked in a scramble.
Melia went over again in the box but nothing was doing, Saints' pressure relentless now, with Shels unable to do much about it. And the best piece of Saints play in the game then resulted in a beautiful, sliced effort by Jamie Lennon shaving the crossbar.
The dynamic, fast play we thought we would see more of this season from Saints has been fleeting but Elbouzedi did everything right with five minutes left, finding Barry Baggley, whose shot was well-blocked by the feet of Conor Kearns.
That was about it, save for big Joey Anang coming up for a corner and heading into the hands of his opposite number Kearns.
Saint Patrick's Athletic: Joseph Anang; Ryan McLaughlin (Axel Sjöberg 46), Joe Redmond, Tom Grivosti, Anto Breslin (Barry Baggley 46); Jamie Lennon, Jay McClelland, Kian Leavy (Zach Elbouzedi 71); Simon Power, Aidan Keena (Conor Carty 85), Jake Mulraney (Mason Melia 46).
Shelbourne: Conor Kearns; Sam Bone, Paddy Barrett, Kameron Ledwidge; Evan Caffrey (Seán Gannon 75), JJ Lunney (Dan Kelly 71), Mark Coyle, Tyreke Wilson (James Norris 75); Harry Wood, Ali Coote (Ellis Chapman 60); Sean Boyd (John Martin 70).
Referee: Paul Norton.
