THERE are those who would have you believe that the biggest game in the next week for Celtic comes not at a rammed Celtic Park this evening against the team currently sitting second in the Bundesliga, but given their patchy start to the Premiership season, at Pittodrie against Aberdeen on Sunday lunchtime.

With Celtic’s current injury list and the status of Bayer Leverkusen as clear favourites to take all three points, there is a suggestion that this Europa League match is something of a problem that Ange Postecoglou could do well without. But at this point, in just their second match of this group section, the Celtic manager isn’t about to give up on this game so easily.

In fact, Postecoglou has served a reminder to his players that it is precisely for nights like these that they are at Celtic for in the first place. So, they had best make the most of it, and make sure they give everything they can to create a night they want to remember for the best possible reasons.

“You are testing yourself against the best, that’s the kind of message we give to the players,” Postecoglou said.

“The worst thing you can do in a game like this is to let it pass you by without really making an impact or taking everything on board.

“You can just go in there and try to survive and just get through the game and then you miss a great experience of testing yourself whether it’s me or the players. For me I look forward to these contests.

“These are the games you want to be involved in and hopefully be successful in and most importantly these are the games you want to test yourself in. That will be the message to the players tomorrow night.”

As well as savouring the experience though, there also has to be a sense of calm from Celtic’s players in dealing with what is in front of them. A quality sorely lacking as they buckled under a rousing Real Betis comeback in their last group fixture.

“It starts with me,” said Postecoglou. “There’s no point me telling the players something that I’m not prepared to do myself. You have to live those behaviours and not just talk about them.

“For us as a group, myself, the coaching staff, the players, everyone involved, what a great opportunity to go up against a fantastic team and see what impact we can make.”

With their emphasis on systems and the prominence they give to structure within their teams, the Bundesliga could almost be made for the coaching style of Postecoglou.

Certainly, the Celtic manager is looking forward to pitting his wits against German opponents after spending much of his life admiring their teams, and he feels there is much that his own men can learn from the likes of Bayer Leverkusen.

In these early days of his tenure, there have been signs of what Postecoglou is driving at, but the patchy results are reflective of the gap that Celtic still to have to bridge between themselves and the calibre of tonight’s opposition.

The link between Postecoglou and Germany extends through his old friend Thomas Broich, the former Borussia Monchengladbach player who worked under him at Brisbane Roar, and who recently called him the best manager he had ever encountered in football.

The admiration is mutual. Postecoglou hasn’t felt the need to go over the heads of Celtic’s opposition analysis team for the lowdown on Leverkusen from Broich though, with his long-standing interest in the German game giving him something of a head start.

“I brought Thomas over to Australia and worked with him for a few years,” he said.

“He was a fantastic player and a fantastic person and he is still involved with football over there.

“We have always got a strong connection with German football in Australia. Quite a few Aussies have been through there and we have had links there.

“In general you understand that the strength of the Bundesliga is such that it’s always a league people follow. Certainly I have because it’s a league which produces fantastic teams and fantastic footballers.

“I think it has always been a system-based league in terms of their best teams always incorporate fantastic individuals.

“Their strongest teams have always been very system based and have clear structures in their football teams.

“My teams are fairly similar in that way and definitely it’s a league where, if you are passionate about football and what is happening, it’s one you follow closely.

“A lot of things they do and the way they work incorporate things that can benefit us.”

A quick look at the likely Leverkusen line-up would be enough to give any Celtic supporters a healthy dose of the fear given their ropey defending of late, with Patrik Schick - he of 50-yard lob against Scotland fame - set to lead the line and German wunderkind Florian Wirtz tucked in behind him.

Winning individual battles against such players may prove beyond some of those available to Postecoglou tonight, so it is unsurprising to hear him talk of the importance of the collective defensive effort that will be required to stifle the gifted visitors.

“I think there will be challenges all over the park,” he said. “The key for us is to not take on those challenges individually but to do it as a collective, whether that’s in midfield, defensively or in an attacking sense.

“It’s really important for us that we’re strong collectively as we were away to Betis and try to take the game to them.

“Ultimately every team, particularly a team like Leverkusen, will want to dominate the game. If we can take away some of that during the night then that gives us the opportunity to make an impact ourselves.

“You always respect the opposition and you always analyse the opposition. Both the collective and the individuals within that. There are going to be individual contests and you want to provide your players with the best possible information.

“They have some fantastic footballers in their team, which is not surprising. They are a great side, a side with great pedigree. They’re a Champions League side in many respects.

“You know that you have to respect the individuals within that, but at the same time you don’t just focus on that.

“We always need to focus on ways we can make an impact within the game and ways we can help our players within that.

“We give them the platform and the opportunity to do that.”