A 92nd-minute Scott Brown winner moments after Hamilton had carved out a far-from-implausible equaliser through Marios Ogkmpoe – coupled with Rangers’ surrender of a two-goal lead at Pittodrie – sparked jubilation.
This was supposed to be a regulation league encounter for a team who had won their previous 10 games in all competitions in dazzling fashion.
But until man-on-a-missionBrown pounced on to a ball 30 yards from goal, dropped his shoulder and drifted past three men before steering a pinpoint effort into the far corner, there was little dazzle about an off-colour Celtic.
Their inability to put away an obdurate and, at times, enterprising Hamilton had only an instant before caused the colour to drain from the home faithful.
An Alexander Gogic throw-in found its way to Ogkmpoe eight yards out on the right and the striker’s aim was true as he poked the ball past Celtic keeper Fraser
What happened next to give Celtic a two-point advantage at the top of the Premiership over an Ibrox side they will meet at Hampden on Sunday meant Celtic’s least impressive performance in two months was their most productive.
Whatever had been said, the line-up fielded by home manager Neil Lennon showed that the Betfred Cup final was firmly in his thoughts.
Against an opponent without a league win in two-and-a-half months, it wasn’t a second string but rather a one-and-a-half string.
Of the 10 outfield players, only half could consider themselves guaranteed starters at Hampden on Sunday: Ryan Christie, James Forrest, Callum McGregor, Scott Brown and Kristoffer Ajer.
Lennon would insist that circumstances outwith the first Old Firm final for his club in eight years impacted on his selection. And it is true that injuries to Odsonne Eduoard, Boli Bolingoli, Mohamed Elyounoussi and Jonny Hayes would have necessitated giving fringe players game time, regardless of when the Hamilton encounter fell.
Nir Bitton filling in for the rested, and benched, Christopher Jullien and Mauritz Bauer deployed at right-back in place of Jeremie Frimpong could only be viewed through the prism of the final.
The performance by this unfamiliar-looking line-up was, er, unfamiliar to those accustomed to Celtic’s sparkling displays during their 10-game unbeaten run.
In part, that must be attributed to the firmness and flexibility of Brian Rice’s Hamilton side, who belied their lowly status – only a point off the bottom ahead of last night’s game – by giving Celtic more moments of concern than French cup winners Rennes at the same venue the previous week.
That resilience was all the more impressive since they conceded an early goal. The suggestion that Christie has become the champions most integral performer had been much discussed online this week.
The attacker is certainly their most invaluable in the vicinty of the opposition goal as he again demonstrated when he was on-hand to bash in a loose ball from close range after keeper Luke Southwood had beat out a Lewis Morgan drive from wide on the left.
That 13th-minute strike was the Highlander’s 16th at club level this season, putting him two ahead of Eduoard.
Hamilton’s response was to grow in confidence and counter-attack with menace. The impressive Lewis Smith galloped 60 yards to put him in dangerous territory that so many recent Celtic opponents have struggled to find.
As Rangers seemed to be on their way to a victory at Pittodrie which would have dislodged Celtic at the top of the table, the home support’s discomfort grew when Fraser Forster elected to kick away a Scott McMann cross that flashed towards his near post.
Celtic did have opportunities – Oliver Ntcham guided the ball wide with the net gaping – but they never had a firm grip of proceedings in the opening period.
That remained true even when substitute Mikey Johnston hit the post midway through the second half – after Forster had to claw away a Sam Stubbs header in desperate fashion.
Other openings were squandered but, ultimately, Brown’s brillance ensured it was not costly.