Goals from Sean Houston and Ciaran O'Connor saw Finn Harps' come from behind at Richmond Park to lift themselves three points clear of the relegation places with a first victory of the SSE Airtricity League Premier Division season.
A third defeat from four games means St Pat's remain in the bottom three as their search for a first win of the campaign continues.
The home side did start much the better, though, gratefully availing of some poor play by Harps to snatch a soft lead goal after just three minutes.
Caolan McAleer and then Jonny Bonner in turn lost possession to allow Saints' midfielder Graham Kelly a free run thorough on goal and he calmly shot the ball past Ciaran Gallagher.
Some frantic Harps defending was needed to prevent that lead being extended on 14 minutes; Gareth Harkin hacking clear a dangerous Billy Dennehy cross after he'd worked a one-two down the left with skipper Ian Bermingham.
But Harps were level from their first attack of note on 19 minutes.
Gavin Peers' headed clearance from a ball in from the right was controlled by Sean Houston before the midfielder drilled his shot low to the corner of the net for a composed finish.
St Pat's almost restored their lead within two minutes. Dennehy's free kick in from the left found Peers unmarked in the area. His shot came back off the crossbar with Kelly shooting the rebound wide.
Harps were well in the game, though, and Michael Barker had to bravely put his body on the line to block Houston's goal-bound drive on 31 minutes after Bermingham carelessly gave the ball away in midfield.
In an open game now, St Pat's threatened on 39 minutes with Conan Byrne just failing to get on the end of JJ Lunney's inviting low cross from the right flank.
But it would be another defensive mistake that brought a third goal with Harps snatching the lead a minute before the interval.
Barker was easily dispossessed by McAleer on the left and the winger ran on to square the ball for striker O'Connor to score with a simple tap in for his third goal of the season
A guilt-edged opportunity to level was spurned by St Pat's inside a minute of the restart. Josh O'Hanlon put Kelly clean through on goal, but the midfielder sliced tamely wide.
St Pat's introduced Kurtis Byrne and then Christy Fagan as they chased the game. But chances remained few and far between as Harps dug in to defend their lead.
Fagan did have a half chance on 70 minutes, but his shot on the turn was well blocked by Killian Cantwell.
The St Pat's striker was then not too far off target with a downward header from Byrne's right flank cross two minutes later as the home side pressed for an equaliser that ever arrived.