CAMERON CARTER-VICKERS hasn’t earned the nickname ‘The Fridge’ from his Celtic teammates for nothing. And while his composure on the ball exudes a certain coolness under pressure, that isn’t the reason behind the moniker either.

Instead, the real explanation is a little less subtle. Simply, he is the size of a rather large industrial one.

“He’s an absolute beast,” said his defensive partner, Carl Starfelt, recently.

That is another descriptive term that has followed him around in his career so far, with Tottenham teammate Jan Vertonghen using it as he assessed his potential way back when the American international was coming through the ranks at Spurs aged just 18.

"He's still young but he's an absolute beast,” Vertonghen said in 2016.

“He's a real defender. He's strong one-on-one, in the air, he's not afraid and he can play from the back. That's the style the gaffer wants to see from him."

It is certainly the style that Celtic manager Ange Postecoglou has seen from him since his loan arrival in the summer, and the style that had endeared him to the Celtic support long before he hit the winner against Rangers on Sunday that looks to have all-but secured the Premiership title for his team.

Celtic have been looking to make Carter-Vickers a permanent fixture in their side for quite some time now, and it is understood that Tottenham won’t be too difficult to deal with when it comes to agreeing a fee for his transfer to Glasgow.

With all sides keen to make the move happen, it seems a matter of when he signs a permanent contract with the club, rather than if.

For former Celtic striker Simon Donnelly, it is a transfer that Celtic simply have to make happen.

“He’s been brilliant,” Donnelly told Sky Sports. “Rock solid is how I like to describe him.

“He’s been really assured, aggressive, physical. It was probably one of his best games for Celtic. He pops up with the goal as well.

“I think if you ask any Celtic fan, they will want the chequebook out and they will want him to become a permanent Celtic player.”

The Celtic defence now is almost unrecognisable to the shaky unit that started the season, with players thrown into games before they had barely remembered one another’s names. It is to Postecoglou’s credit that he stood by the central defensive pairing at the heart of it all, particularly when they were coming under fire in the early part of this campaign.

In fairness, it was Starfelt who was attracting most of that criticism after a few high-profile mistakes, but Carter-Vickers has been the rock at the centre of all Celtic’s good defensive work since then, and the fruits of persevering with that partnership were laid bare at Ibrox on Sunday.

Rangers had to win the game, and in the second half, they threw everything but the kitchen sink at their city rivals. Mostly from the flanks.

Cross after cross was thrown into the Celtic area, and cross after cross was repelled by Carter-Vickers and Starfelt.

“Starfelt made a couple of mistakes at the beginning of his tenure at Celtic, and [after] a couple of heavy defeats in Europe, everybody started to criticise Celtic’s defence,” Donnelly continued.

“They’ve got the best defence in the Scottish Premiership, and [on Sunday] when questions were asked, I thought they were brilliant. I thought (Greg) Taylor had a really good performance as well.

“I think there were 40-odd crosses came into the box, more in the second half, and time and time again Starfelt or Carter-Vickers were there. I think Joe Hart had one save, a really good save, from (Fashion) Sakala.

“When you go to places like Ibrox you are going to have to defend, you are going to have to work hard, and I thought they did that to a man Celtic, and that’s why they got the result.”

Given that there were only two starters in the Celtic team that took to the field in the last Old Firm derby at Ibrox of last season when they fell to a 4-1 defeat, in captain Callum McGregor and left-back Taylor, the turnaround in their fortunes to get to this point has been as striking as it has been unexpected.

The likes of Carter-Vickers, Starfelt and a host of others have now been integrated into a unit capable of such a performance as they put in at Ibrox, one which was notable not for its fluency on the ball, but in the willingness of this group of players – flung together in the summer and in January – to give their all for their teammates and for the cause.

Donnelly, perhaps still slightly giddy from the euphoria of Sunday’s win, is a little disbelieving of what he is witnessing.

“I don’t think the most fervent Celtic fan would have anticipated this turnaround so quickly,” he said. “It’s been incredible really.

“But I think the recruitment, the work ethic, the way Ange has went about this, he deserves all the credit.

“Celtic have been good to watch this year as well. They talk about ‘the Celtic way’, the attacking free-flowing football, and they’ve had that.

“They showed [against Rangers] that they have that dig about them as well, and to be on the cusp of a potential Treble, it’s an incredible turnaround.”