Former Celtic and Rosenborg striker Harald Brattbakk: "Champions League tie will still be alive going to Trondheim"

That resulted in a revolt from within the dressing room as the Rosenborg players issued a statement calling on Ingebrigtsen to be re-instated.

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That plea was ignored by the Rosenborg board and there appears to be a bitter civil war within the club as they prepare for tomorrow night’s opening leg against Celtic in Glasgow.

Brattbakk, though, believes that the potential of progression into the third qualification phase can offer a focus and some respite from the feud for those who will head onto the pitch.

“Mike Jensen, the captain, said yesterday that the main focus now has to be to stay professional and that is the message that I think they have to take on board,” said the former striker who now works as a pilot.

“It is not an easy situation for anyone but perhaps the easiest thing to do is to get out on the pitch and play football. That is what they are paid to do. Regardless of who the manager is the players have a responsibility to perform to the best of their ability.

“I am lucky enough to have experienced Celtic Park both as a Celtic player and as Rosenborg player. It is an amazing stadium, a fabulous ground and while the home support should give Celtic an edge, it should surely be something that excites the Rosenborg players too.

“The bottom line is that they are playing for progression in the Champions League. It is the big prize for all players. But it is a big test. Tomorrow night we will see just how the last week has affected the players.”

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The clubs met at the same stage of the qualification process a year ago with a solitary James Forrest goal in Trondheim the difference between the sides. Neither squad has had significant surgery since then although both are hindered on Wednesday night due to injury and suspension issues.

Celtic are without the experience of Jozo Simunovic who is suspended after his red card in the second leg against Alashkert last Wednesday while Dedryck Boyata has been granted additional leave after his performances with Belgium at the FIFA World Cup in Russia. Marvin Compper has an adductor injury which has left Celtic with little cover defensively.

“One of the reasons the board cited for the dismissal of Kare Ingebrigtsen was the lack of progress made by the team in the last 12 months,” said Brattbakk. “I haven’t seen as much of Celtic so I can’t comment on how they might have inproved but what I will say is that when it comes to two games in isolation then what has happened over the last year is irrelevant.

“I will also predict that this game won’t be finished after the first-leg tomorrow night. I fully expect that Rosenborg will put up some kind of fight to keep the tie still relevant in the second leg. Like Celtic, they have injuries too and it has not been the ideal way to prepare for a game of this magnitude. But the prize is significant.”

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Kristoffer Ajer will be expected to feature at the heart of Celtic’s defence tomorrow night, with Brattbakk pleased to chart the progress the 20-year-old Norwegian has made under the tutelage of Brendan Rodgers.

“He has made great strides and when you are a young player who is given the chance to play, then you really do see those big developments,” said Brattbakk. “He has come into the national team and performed well and he needs to concentrate now on maintaining that progress.

“It will be interesting for him to play against players he plays alongside with Norway but it won’t affect him. If he has a poor game it won’t be because there has been a lot of interest in him from Norway. It will be a different experience for him to have so much focus in the build-up but he is a football player. The minute he steps onto the pitch he will concentrate only on playing the game in front of him and not who is watching.”