Save for the fact that they would like a few more signings in the door before the end of the transfer window, there can hardly be a cloud in the sky for Celtic supporters just at the minute.

Their team have started the season in formidable fashion, and they continued their impressive form with a second routine swatting aside of Hibernian within a week on Sunday to book another home tie against Championship side Falkirk in the quarter finals of the Premier Sports Cup.

Adam Idah is back in the squad, with the striker given a rapturous reception as he made his second Celtic Park bow off the bench at the weekend, while for all the speculation surrounding Matt O’Riley, he too remains a Celtic player. Even if he does leave over the next 11 days, a fee approaching a club record will be received by way of compensation.

So, it was little wonder then that the mood music around the stadium was markedly different to that around Hampden 24 hours previously, as city rivals Rangers booked their own place in the last eight of the League Cup.

There was one man though who had something eating away at him following the win over Hibs at Celtic Park, and the source of his annoyance may well say a lot about why Brendan Rodgers’ men are currently steamrollering any opposition that is in their path.

Despite the 3-1 win, the goal that Celtic conceded was uppermost in the thoughts of centre back Cameron Carter-Vickers. It was he who gave away the free kick that led to Hibs finding the net, clattering through visiting striker Mykola Kukharevych, who produced a stunning diving header from Martin Boyle's delivery beyond Kasper Schmeichel to momentarily haul the Hibees back into the contest.

It was the first goal that Celtic had conceded in their three competitive matches so far this term, and ended up but a footnote to the game as the hosts took control once more and won comfortably. But even still, it was clearly eating away at the big American as he assessed the match afterwards.

“It is annoying,” Carter-Vickers said.

“Maybe Hibs had a few half chances, but apart from that I don't think they had too much from open play.

“It's definitely annoying to concede from a set-piece, but again, it's something we can look at. I think normally set pieces are easily corrected, so it's something we can definitely look at and improve on.

“I thought it was a pretty good performance overall. Throughout the game we maintained our level. I was disappointed to concede the goal, but apart from that I thought it was pretty good.”

While the concession of that goal may have been avoidable from a Celtic perspective, Carter-Vickers is however pleased by how the Celtic defence is currently shaping up, with his developing partnership with Liam Scales a key factor in the solidity they have generally been displaying of late.

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“Like I said last year, any partnership, especially defensive partnerships, takes time to learn each other's games,” he said.

“Things then become a bit more instinctive instead of waiting. I think that's definitely happened with me and Scalesy. So far this season it's gone well, and hopefully that continues.”

There are signs in fact that the pair are building up the same sort of understanding that Carter-Vickers had with Carl Starfelt, the partnership that was the bedrock of Celtic’s success under Ange Postecoglou.

“It's always hard to compare different teams, different seasons,” he said.

“But like I said, it's just about that constant want to improve and work with each other and understand each other more, and that's what we're trying to do.”

Another key factor in Celtic’s defensive resolve, in Carter-Vickers’ view, is the seamless transition behind him, with Kasper Schmeichel coming in and filling the void left behind by Joe Hart’s retirement with minimal fuss or upheaval to the team.

“Kasper's been really good,” he said.

“I think from the minute he came in, you saw his quality. I think it's clear to see that on the ball, he can play with the ball at his feet.

“He probably hasn't had to make many big saves yet in the league or the cup game, but I think you saw in pre-season some of the saves he made were unbelievable, so I'm definitely enjoying playing with him and looking forward to keeping playing with him.”

So, that Kukharevych goal aside, everything in the Celtic garden appears rosy at the moment. And with the players now starting to carry out the instructions of manager Rodgers almost reflexively, Carter-Vickers thinks that their level can only rise even further.

“I think we're definitely capable of more,” he said.

“We’ve started well, it's kind of been a continuation from pre-season, but hopefully as the season goes on and we continue to work together, we'll improve and get better.

“Our performances so far have been good, as well as the ones in pre-season. It's early, so for us it's just about continuing to try to work and try to improve. That's what we've been doing so far, and if we continue doing that we'll be in a good place.

“Since it’s the manager's second year now, I think it's only natural that the more time he gets with the group, the more he can implement the way he wants to play and the way he wants to train and work.

“I think we're in a good place. We haven’t had any injuries yet, we're just continuing to crack away and trying to get better.

“Every day of training is tough, and we go out there ready to work, and as long as we keep doing that, we're in a good place.”