FIREWORKS the night before. Broken glass holding up play. Coins and cups launched at players. Planes flying overhead urging a push for the title. A whirlwind start that had Celtic floundering and on the ropes.

Aaron Ramsay’s opener could have been followed by a second in those frantic, fierce moments of the game when Celtic seemed spooked and static as Rangers flew into the opening minutes. A screenshot that picked out Josip Juranovic close up showed the Croatian full-back’s ghostly pallor, as white as the underbelly of a flapping fish.

His unease was shared by a Celtic side who writhed uncomfortably in Rangers’ net. The home support scented their weakness and demanded its exploitation.

And what was notable about Celtic’s ability to find a way off the hook in that early Ibrox storm was where it came from.

Much has been written about Callum McGregor this season and how he has assumed the captaincy role at the club. If he showed a particular kind of leadership with the donning of a mask as he played with a double fracture in his cheek in February when the teams met at Celtic Park, he exuded a different kind of bravery on Sunday.

It was the midfielder’s driving run that brought a leveller in the game, crucially quick as Celtic steadied themselves. Their early resolve quietened; Rangers struggled to impose themselves across the remainder of the 90 minutes in the same way that they had in those opening five. It is impossible to overstate just how important McGregor was in guiding Celtic back onto solid ground.

The outcome of this game always felt season-defining. And few now would bet against a Celtic side that have now gone unbeaten in 32 domestic games going on to win the title.

The opening to this game felt like Celtic’s season in microcosm. Having lost three of their opening six league games, they were chasing shadows in those chaotic early weeks. That they steadied to overhaul Rangers points to a belief within the squad; within one another and within the manager.

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'We do not stop' has become Ange Postecoglou’s trademark after that opening Lennoxtown training session. Carl Starfelt was the latest to quote it as the Celtic players celebrated inside Ibrox with recovery ice baths.

That mentality, though, may be particular crucial now as Celtic head into the final six league games of the season. Offering little encouragement now to Rangers will be key as they look to claim the title. 

If the win over Rangers at Celtic Park in February was a stylish and swashbuckling victory, the win at Ibrox – the first team to beat Rangers on their own patch in the league for more than two years – was a different kind of victory.

Celtic have been applauded this term for their ability to accelerate from middle to front. In full flow, they have been dizzying to watch at times.

But it was the steel they had about them defensively as they produced a performance which was one of conviction and resoluteness. If the Parkhead game against Rangers was all about the goals and the aggression of Celtic when they are in full flow, Sunday’s victory showed their other side with Cameron Carter-Vickers and Carl Starfelt standing up to everything that came their way.

If winning the league unlocks the bounty of Champions League football and the financial return that brings then it would be wise for Celtic to continue the investment made this season. Postecouglou could do little more to show that he can be trusted when it comes to identifying players.

Carter-Vickers’ performance was sufficient to ensure that he left with the man-of-the-match honours. A loan signing this term he has been a quiet mainstay in a Celtic side who have matured rapidly over the last six months.

Realistically can Celtic afford to keep him? They certainly need to be seen to ask the question. The over-inflated English market may well price Postecoglou out of a deal for the defender – and it is worth remembering he shared a dressing room with players whom a six-figure weekly wage is the going rate – but the possibility of keeping a defensive partnership together that can boast the most miserly record in the league would be sensible.

The immediate plan, though, is to continue through a month that Celtic will feel is alive with possibility.