Amid a truly extraordinary palaver about the identity of the scorer of the all-important goal, one fact remained untroubled by ambiguity.
Never in the history of the Scottish game has a club viewed Hampden as a second home quite like Celtic in three now going on four seasons.
When Neil Lennon takes his side back to Mount Florida on April 11 or 12 to face Aberdeen, it will be the 15th time they have decanted there since 2016. It would be a brave man to wager against a subsequent visit by the time this term is out.
Ryan Christie scored a late goal to send Celtic through to the next round of the Scottish Cup
There was some confusion over the scorer as Christopher Jullien may have got a touch
St Johnstone 4-4-2: Clark, Kerr, Gordon, McCart, Wright, McCann, Butcher, Wotherspoon (O'Halloran 83), Tanser, May, Hendry (Kane 77)
Subs not used: Swanson, Parish, Holt, Booth, Craig
Yellows: Gordon, McCart, Butcher, Hendry
Celtic 3-5-2: Forster, Ajer, Jullien, Bitton, Taylor (Hayes 76), McGregor, Brown, Christie, Forrest, Eduoard (Bayo 87), Griffiths (Rogic 65)
Subs not used: Klimala, Bain, Frimpong, Elhamed
Goals: Christie 81
Yellows: Bitton, Forster
This slender victory in Perth saw Celtic rack up a 34th successive victory in domestic cups competitions. To suggest they have lately found a way to such affairs is to indulge in stating the blindingly obvious.
Few assignments along the way will have been as arduous as this one. St Johnstone did more than just stay alive until the game ended its closing stages. For long periods, on a truly treacherous surface, they gave as good as they got.
Just nine minutes separated them from the chance to do it all again in Glasgow only for Celtic to continue their happy habit of getting their noses over the line.
Ryan Christie's free-kick might well have nestled in the rigging in any event. Christopher Jullien took a swipe at it and may even had grazed the ball with his stud.
The confusion and debate over who had the final touch was still raging last night but it will quickly become a mere footnote in this season. Yet again, Celtic prevailed.
The goal came form a free-kick, taken by Christie with Jullien possibly getting a stud on it
Europe may have gone for Lennon's men for another year but the possibility of a fourth successive Treble is very much alive.
Celtic v Aberdeen
Hearts v Hibernian
In that regard, you can only admire the huge psychological strength of the champions. The unforeseen home loss to Copenhagen on Thursday was deeply wounding for all concerned but this, the very epitome of a hard-fought win, was just so typical of what the side has produced throughout this extraordinary period of dominance.
Even on a quagmire of a pitch at McDiarmid Park, the energy of the returning Christie still shone through.
Suspended for the European reverse, the midfielder served notice of what was to come by sending an early effort curling just beyond Zander Clark's far post as Celtic tried to replicate the fast starts of so many of their recent trips to Perth.
Saints had got a deserved point from Rangers seven days previously largely through their manager Tommy Wright pairing Stevie May with Callum Hendry in an orthodox 4-4-2 and that bold approach again asked questions of visitors from Glasgow.
St Johnstone were not without their chances, as Fraser Forster was tested a few times
May's strong hold-up play allowed his partner to work Fraser Forster with a shot which the keeper only scooped out as far as Matt Butcher. Fortunately for the Celtic keeper, the midfielder's effort ran harmlessly wide when he ought to have done better.sonos sonos One (Gen 2) - Voice Controlled Smart Speaker with Amazon Alexa Built-in - Black read more
It was not a day for