THE red card that Jozo Simunovic received against Alashkert on Wednesday evening had little to no effect on Celtic’s procession to the next round of Champions League qualifying, but the subsequent suspension may give rise to some trepidation among supporters about their longer-term ambitions in the competition.

The centre-back will sit out of next week’s first leg against the Norwegian champions at Celtic Park, a headache that manager Brendan Rodgers admitted afterwards that he could do well without given that Dedryck Boyata and Mikael Lustig are still likely to be absent after their World Cup exertions with Belgium and Sweden respectively, while Marvin Compper has injured an abductor and Nir Bitton – the midfielder who last season filled in at centre-back at the same stage – won’t be seen until September due to injury.

Read more: Celtic defender Jozo Simunovic won't learn full European fate until next Friday​

The burden of leading what is shaping up to be an inexperienced back three on Wednesday night will fall upon the likes of Kristoffer Ajer, but the young Norwegian is relaxed about the prospect of facing up to his countrymen.

His manager’s attention to detail led to his side coasting to victory even after they had lost Simunovic against the Armenians, and Ajer has faith that if he can focus on the plan that Rodgers puts in place for the challenge ahead next week, that Celtic will be able to cope with whatever is thrown at them.

“[The sending off] made things more difficult,” Ajer said. “But we always have a plan for when that happens during a season. I felt we stayed in control still with 10 men and we scored some great goals.

“You know when you play Champions League qualifiers all games can be really hard. To win both games 3-0 was a good performance and we’re happy to go through.

“[The manager] just makes sure you know that every time you play for Celtic it’s a big game. When you put on that shirt you always need to put on a top performance. That’s what we hope to do.

“When you play for Celtic you always need to put on a top performance to keep your spot in the team. I just need to be 100-per-cent focused over the next few days. Hopefully everyone else can stay fit and we’ll be raring to go.”

Read more: Celtic defender Jozo Simunovic won't learn full European fate until next Friday​

Ajer is expecting a step up in the challenge that Celtic will face as they take on the champions of his homeland. Despite the turmoil caused by the sacking of manager Kare Ingebrigtsen last night after their progression to the second round was only delivered via a 93rd-minute penalty in the second leg against Icelandic side Valur on Wednesday, Ajer expects them to very much adhere to the stereotypical perception of Scandinavian sides as being well-organised and well-structured above all else.

“Rosenborg is a really tough opponent with a lot of quality players,” he said. “It will be a really tough game both home and away.

“When you play Champions League qualifiers you meet quality opponents. I know Rosenborg really well and last year they beat Ajax in the last [Europa League qualifying] round to go through, so they’re really a top side. They can really hurt you if you’re not 100-per-cent up for the game.

“But we know that. When they come here next week then hopefully we’ll put on a really top performance. We also know that they’re a great team. 

Rosenborg is a typical Scandinavian team: they are well organised and have a good squad. So that’s probably their biggest strength.

“I think they have many good players. But it’s a well-built team. There is a really clear structure. I think they have a really good team that will make it difficult for us.”

The vast majority of the Celtic squad know only too well how tough a task awaits them, having edged out Rosenborg at the same qualifying stage last summer by a single James Forrest goal over the two legs of the tie.

And Ajer is expecting this year’s rematch to be just as tense and tight as it was 12 months ago.

Read more: Celtic defender Jozo Simunovic won't learn full European fate until next Friday​

“I think it will be [a difficult match],” he said. “Rosenborg will come here and make it difficult for us and also over there. They will be tight games; they’re a good side.

“Obviously, it helps us knowing a little bit more about the team. Since then they’ve made some team changes, a few more signings. Obviously, we’ve also had some signings too, so it’s slightly different.

“But, we know them better than we did last year.”

For Ajer, the return leg will of course be a homecoming, and the 20-year-old,  who signed for Celtic from Norwegian rivals IK Start in 2016, is bracing himself for the imminent flood of requests for tickets from friends and family back in Norway.

“I haven’t [had any] yet, but they will probably come!” he said, laughing. “Obviously I like going home and it will be nice returning to Norway. But I play for Celtic and I’m just looking forward to the two games. Rosenborg will make it difficult for us and it will be an exciting game. Rosenborg have always been a top team in Norway.”