PRES joined CBC in the semi-finals of the Pinergy Munster Schools Junior Cup after eventually wearing down a spirited Castletroy College at Musgrave Park on Thursday.
The scoreline didn't reflect the Limerick team's contribution to a fiercely contested encounter, particularly at the breakdown.
Hooker Cian Kennedy, second-row Adam Dooly and number eight Aaran Cregan epitomised their approach though there was no disputing Pres's victory.
Captain Rory Moloney led by example and out-half Harry Murphy and centre James O'Leary were others to make favourable impressions.
Pres led 8-0 at half-time after playing against the strong wind and facing a defiant Castletroy, who defended stoutly.
An early driving maul showed the potential in the Pres pack and but for last-ditch tackling, the Cork side would have jumped in front.
Prop Fionn O'Sullivan was held on the line and when Castletroy's 22 drop-out cleared the touchline, Pres couldn't avail of the subsequent five-metre scrum.
Their pressure finally yielded the opening score, Murphy landing a 14th-minute penalty after the Limerick side infringed in a ruck.
It was Pres's turn, then, to show their defensive traits as Castletroy found a superb touch through Joel Rowndtree only to meet stubborn resistance.
Defence switched to attack with wing Ali Dunne sweeping down the left in an impressive burst of speed and only a last-gasp tackle stopped him in his tracks.
And on the other flank, with Dunne involved in the build-up, Evan O'Dowd just clipped the touchline, but the breakthrough finally came after 22 minutes.
A loose clearance kick offered Pres the chance and they moved the ball through the hands for O'Leary to send his midfield partner Mark Hetherington in at the Sundays Well corner with Murphy's difficult convert dropping short.
Castletroy had a chance just before the interval when forcing an attacking scrum deep in the Pres 22, but the home side stood firm.
And it was the same case on the resumption, Castletroy on the front foot in a promising position only to meet stubborn resistance.
Pres made the game safe in the closing 10 minutes, Murphy kicking a penalty for 11-0 before O'Leary's strength and pace earned a second try, converted by Murphy.
The result paves the way for the two games in the quarter-finals.
Rockwell College, who defeated Bandon Grammar School 19-17 on Wednesday, take on Crescent College Comprehensive.
St Munchin's, who defeated Ardscoil Ris 32-5, scoring four tries in the process, face Castletroy in the other.
CBC, who overwhelmed under-strength Crescent, will be on one side of the semi-final draw with Pres on the other.
Tries: M Hetherington and J O'Leary. Con: H Murphy Pens: H Murphy (2).
JP Curtin; E O'Dowd, M Hetherington, J O'Leary, vice-captain, A Dunne; H Murphy, vice-captain, R Byrd; S MacFarlane, L Hegarty, F O'Sullivan; C Donnelly, D Murphy; B Foley, R Moloney, captain.
D Sheehy, I Crowley, S Gilbert, P Walsh, R Porter, F Og Sheahan, H Murphy, R Byrne, D Fitzgerald, J Cashman.
R Widger; S Lyons, L Glynn, J Rowndtree, A Kearney; B Toland, C Williams; J O'Gorman, C Kennedy, J Conway; B Fogerty, A Dooly; C Purcell, A Cregan, D McMahon.
C O'Hanlon, Travis Tchokotieu, Trevor Tchokotieu, A Power, J Sheehan, J O'Malley, A Rmblado, R Brady, J Rennison, P Walter.
P Sheehan (MAR).