He's not quite there yet, but Carl Starfelt feels he's on the cusp of putting a difficult few months behind him for good.

The Celtic defender's season has been a truncated one, all thanks to a knee problem that sidelined him for around eight weeks. Then, just as he was settling back into life away from the Parkhead treatment table, the Premiership shut down for the small matter of the World Cup.

With Sweden failing to earn themselves a ticket to Qatar, it was back to Lennoxtown for Starfelt. But there's nothing like playing games and the centre-back believes he needs a consistent run before we see the very best of him once more.

There are certainly opportunities to do so at this time of year, with Celtic playing twice a week for the next number of weeks in the league and Scottish Cup.

“I felt I had some good weeks of training during the break," Starfelt said. "And, while I am not yet 100 per cent, I feel I am getting back there.

“You need to play games and I feel my best after a few weeks of consistently playing. Physically I feel good and I feel that I’m in a good place.”

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If selected on Wednesday, Starfelt will likely reunite with Kevin Nisbet, 10 months after a tackle from the Celtic man left the Hibs striker with a knee ligament injury he's only recently returned from. It was an incident that drew criticism from former Easter Road boss Shaun Maloney at the time, but while Starfelt expressed sympathy with Nisbet, he's adamant there was nothing "nasty" about his challenge.

"It was really sad to see that he got a bad injury," the defender said. "You don’t want to be involved in that kind of injury. I know how hard it is to be kept out of the game. I felt really sorry for him, but I cannot see how you can say that it was a nasty challenge. It was not intended at all.”

Ange Postecoglou has regularly rotated a squad littered with talent this season, and it's a policy that ensures slacking off becomes an option for absolutely no one. It will mean some players may not rack up the minutes they'd like to, but Starfelt maintains it cannot be any other way at a club of Celtic's stature.

"It’s not only my position," he said. "It’s almost all of the positions. It keeps everyone a little bit on the edge. You know that you cannot relax in games or in training. In games, it is a bit more natural to give 100 per cent but also in training you need to be really at it. It’s good. At a club like Celtic, that’s how it should be.

"We need to keep improving. We always want to evolve. We want to do big things so we need to keep improving. You could see that in the Champions League. Now, it’s domestic this year, but long term we want to keep improving and be able to give even more in the European competitions."

But you do get the feeling Starfelt would prefer some consistency of selection at the back; namely one that involves him and Cameron Carter-Vickers alongside each other. Moritz Jenz arrived on-loan in the summer, Stephen Welsh is still staking a claim, and now Yuki Kobayashi has arrived to add to the ever-growing Japanese contingent in Glasgow's east end.

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“We are all aware of how we want to play," the Swede said. "You do want that consistency in the back line. You want to get to know each other and work as a unit.

“No matter who comes in it is very clear what you should do. Reo Hatate came in at full-back against St Johnstone and he adapted really well.

"Cameron is a really good player and I’ve enjoyed playing with him since he came. I feel like we have a good chemistry on and off the pitch. We see many situations the same way. He’s a very strong player. You always know what you will get from him. He’s easy to play with."

Celtic have been in truly imperious domestic form this season, with or without Starfelt. Postecoglou's side lead the Premiership by nine points, having won 17 of their 18 league outings so far. Unsurprisingly, they currently boast the best attacking and defensive records in the division.

The reigning champions have conceded 15 times in those matches, keeping clean sheets on eight occasions. It feels like nit-picking to seriously suggest any sort of improvement is required from a team who look borderline unstoppable. But Celtic's success under Postecoglou has been built on striving for perfection, and Starfelt believes they can do more to keep the back door shut.

They conceded a soft goal against St Johnstone at the weekend, allowing Stevie May to escape in behind before Drey Wright finished on the rebound. It was a mere consolation for the visitors, who were 4-0 down at the time, but it left Starfelt feeling "irritated", and he is keen to ensure Celtic leave Easter Road this evening without a blot on their defensive copybook.

“The most important thing is the performance and winning the game," he said. "But, I do want to keep clean sheets. It is a little bit irritating when we concede. It is about addressing it and keep working hard to make sure we keep more going forward.“