This winner-takes-all affair was always going to be keenly contested and while Na Piarsaigh advance to the quarter-finals, Patrickswell must battle for senior survival against Croom.
Making the Na Piarsaigh success all the more remarkable is that they lined out without injured inter-county men Shane Dowling and Kevin Downes.
Their hero, instead, came in the form of the evergreen Damien Quigley. The 1994 All Star hit 0-3 for the winners and created the all-important goal for Kevin Ryan.
That 21st-minute major set Na Piarsaigh on their way to a 1-9 to 0-5 interval lead.
It was an opening half that saw Patrickswell fail to score from play, with free-taker Jack Kelleher accounting for their entire tally.
Kelleher and Patrickswell had started brightly and led 0-3 to 0-1 after five minutes, but went scoreless over the ensuing 20 minutes as Na Piarsaigh assumed control.
Their full-forward trio of Quigley, Adrian Breen and David Sheppard hit 0-2 each to stretch their advantage to seven.
Patrickswell made wholesale personal and positional switches at the break and they had the desired result, with both half-time replacements Lar Considine and Cian Lynch finding the target early at the change of ends.
Within five minutes of the restart the lead was cut to 1-9 to 0-8, but Na Piarsaigh hit back with Alan Dempsey and free-taker Pat Gleeson steadying the nerves.
Entering the final quarter the scorebaord read 1-12 to 0-8, with a flurry of wides hindering the progress of Patrickswell.
Approaching the finish, however, Patrickswell received the perfect tonic when Lar Considine scrambled to the net after a succession of chances were saved.
Only four points now separated the sides and a white flag from Lynch in the subsequent action further eroded Na Piarsaigh’s lead with just under 10-minutes to play.
But that’s when Na Piarsaigh turned the screw on their opponents’ revival.
Alan Dempsey fired over two points and Dowling also got on the scoresheet to move six clear and secure a place in the knockout stages.
Scorers for Na Piarsaigh: P Gleeson 0-6 (4f, 1 65), D Quigley, A Dempsey 0-3 each, K Ryan 1-0, D Sheppard, A Breen and S Dowling 0-2 each.
Scorers for Patrickswell: J Kelleher 0-6 (5f, 1 65), L Considine 1-2, C Lynch 0-2, K O’Brien and M Carmody 0-1each.
NA PIARSAIGH: P Kennedy; N Buckley, K Breen, K Bermingham; C King, D Breen, J O’Brien; P Gleeson, A Dempsey; K Kennedy, K Ryan, J Madden; D Sheppard, D Quigley, A Breen.
Subs: S Dowling for Sheppard (36), D Dempsey for Kennedy (44), W O’Donoghue for Gleeson (50), B Hartnett for Bermingham (58).
PATRICKSWELL: B Murray; P O’Reilly, P Mann, T Nolan; E Foley, J Mann, D Byrnes; S O’Brien, M Carmody; J Kelleher, T Sheehan, K O’Brien; P Howard, B Foley, T O’Brien.
Subs: C Lynch for Sheehan (h-t), L Considine for Howard (h-t), P O’Grady for B Foley (40), A Carroll for Kelleher (56).
Referee: D O’Driscoll.