Experience trumped youthful exuberance in a drama one could not take an eye off in Tallaght, Shamrock Rovers maintaining their lead at the top of the table - just.
Luck was on the Saints' side when they went ahead through Mark Doyle on 28 minutes but they had been excellent in a first half they ruined by the concession of a needless goal at its conclusion, Lee Grace heading home.
Richie Towell had the champions back in front on 68 minutes but a blunder from goalkeeper Leon Pohls allowed substitute Ben McCormack to steal in with six minutes to go and equalise - seemingly earning the away side a point.
Yet Rovers were somehow ahead again on 88 minutes, Towell scoring from the spot after Tom Grivosti had bundled down Johnny Kenny in a breathless conclusion to a cracking game.
It was more about drama than quality, perhaps, but epitomised why 6,212 fans paid in on a Monday night, and both sides can take plenty from this game going forward, including interim Saints manager Jon Daly.
Saints welcomed back veteran striker and former Hoop Eoin Doyle from suspension. Mason Melia, who became the club's youngest-ever player on Friday night when appearing in the win over Drogheda, was absent due to his involvement with the Ireland under-17s, who are about to begin their European Championship campaign.
The Tallaght crowd included FAI CEO Jonathan Hill, who will be keenly interested in how the Irish get on in Hungary, most of them playing in the League of Ireland.
Pat's did, however, name two of the country's brightest prospects - Adam Murphy and Sam Curtis - in their starting 11; both would have nights that advertised their talents and lack of experience.
The champions played a far more experienced starting side, with five players in their 30s named in a team on a splendid run of form.
With Trevor Clarke suspended, Ronan Finn started; both he and Neil Farrugia played more like wide strikers than wing-backs in the early stages.
The game's first opening came on 19 minutes. A smashing Jamie Lennon tackle robbed Gary O'Neill and Chris Forrester, as few in this league are capable of, was able to pick out Jay McLelland, but Pico Lopes just got back to block.
Saints had much the best of it midway through the half but Jack Byrne fired a warning shot on 27 minutes, failing to trouble Dean Lyness. The opening goal was all or much about Saints pressure, again Lennon heavily influential.
Graham Burke coughed up possession and Doyle deceived Leon Pohls thanks to a wild deflection off Lopes and the help of the post nearest to the delirious away section.
Byrne's free-kick found Grace on 35 minutes but Lyness gathered the header easily and Rovers to this point had not created a proper opening of note.
Lennon was the first half's outstanding player and it was a question of whether he and the Saints could keep up their work-rate in the second half.
It looked as though they'd go in ahead at the break but they gave away a silly goal right on the interval.
Curtis, rather than clear his lines, showed his inexperience by trying to let the ball go out for a corner but the ball was barely moving and Neil Farrugia nicked it off him, playing in Burke who forced a fine Lyness save.
From Byrne's corner, Grace headed home from close range.
The cultured left pegs of both McLelland and Farrugia kept the fans on the edge of their seats in the first ten minutes of the second half of a match beautifully up for grabs.
That Saints could spring Serge Atakayi, who scored at this venue late last season, and the impressive Jake Mulraney off the bench with 25 minutes to go advertised that Daly wanted three points here rather than settle for one.
However, he'd have settled for the one moments later. This time it was two of Rovers' senior pros, Ronan Finn and Towell, combining.
Saints' defending betrayed the difficulty in tracking runners from midfield but Finn's cross was poetry. Towell was on hand not only to score but to wind up the Saints fans who had tried to do the same to him for the previous hour.
The crowd was on its feet with 15 minutes to go as two of the league's fastest players, Farrugia and Atakayi, chased a ball that was cleared from a Hoops corner-kick.
Farrugia's backpass had roughly the same conviction as Atakayi's poor finish with only Pohls to beat - a pivotal moment. Pohls will not be happy with his intervention with six minutes to go as Curtis' shot was pretty tame but his parry gave McCormack the chance to blast home from close range.
The drama was far from over. Rovers had already nearly equalised before Grivosti bundled substitute Kenny over after a Lyness save, Byrne blasting the ball into the net but almost exactly at the same time as referee Damien MacGraith, who generally had an excellent game, had blown for a penalty.
Towell was cool as ice from the spot, less so in again celebrating in front of the Saints fans - but that's just an example of another reason why we love the League of Ireland.
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