At six foot five inches in his stocking feet, Kristoffer Ajer doesn’t look like an obvious candidate for a mugging. And the Celtic defender was adamant that there was no way anyone was stealing his moment as he netted the opening goal against Estonian minnows Nomme Kalju. Leigh Griffiths seemed to initially try to pinch the credit with Ajer quickly shooshing him off.

"I can't believe they are trying to take the goal off me again,” joked the Norwegian defender. "I have scored twice now and Scott Sinclair has tried to claim one, and Griff the other. That's strikers for you but it's all good.”

Ajer’s bigger fight might not be in claiming goals but in hanging on to his shirt. The 21-year-old has matured over the last season and has become a trusted member of the Celtic backline but with Christopher Julien waiting on the wings and further arrivals anticipated in this window, the expectancy is that there will be competition for places.

That may alter somewhat if Lille’s interest in Jozo Simunovic crystalises. The Croatian defender is suspended for Celtic’s opening two league games against St Johnstone and Motherwell after a reckless red card against St Gallen earlier this month in a friendly.

That will open the door to a different defensive partnership with Ajer keen to ensure he makes his mark.

"It's a really healthy mindset to not think you are better than the last game you played,” he said. "There are a lot of top-quality centre halves ready to take your place if you don't perform. I know that every single time I go on the pitch I need to perform and that's what will keep driving me on to become better.

“Chris [Julien] will bring great experience to the team. He has been good in training and he is a great leader. He talks a lot and he will bring a lot to us, for sure.”

It is a measure of Ajer’s progress that there was a nervousness about the support this time a year ago when Dedryck Boyata was in meltdown as he tried to force an exit from the club. There were question marks over Ajer’s suitability going into the Champions League qualifiers whereas this term there appears to be a level of confidence shown in the 21-year-old.

"It's normal when you are a young player and you haven't proved you can play that there will be doubts,” he said. "You have to play games to show you are good enough but I feel I have now taken steps. The more games I play, the more I learn the role. So I feel much better than I did 12 months ago.

"Do I feel the fans trust me now? Yes, but there is always the expectation to go and perform every single week. That's one of the best things about playing for Celtic - there is always pressure. You can never be complacent and I really enjoy that.”

John Kennedy has been a willing tutor for the youngster who has moved back from central midfield. The former Celtic defender has worked with Ajer on the training ground, with the Norwegian internationalist a willing listener.

"I have been working closely with John Kennedy from day one at Celtic,” said Ajer. "We speak after every single session and we look at clips following every match, to help develop my game. He has been unbelievable for me and he is a great person to learn from. It's good that he has stayed on under the new gaffer. He's a very professional guy and every single player in the squad respects him."