If you know your history, then the Celtic supporters are well aware that this is the third time that Brendan Rodgers's team has conceded seven goals in a European match.

For the record, the Irishman lost 7-0 in the Camp Nou to Barcelona back in September 2016, which incidentally is Celtic's heaviest-ever European defeat. The Scottish champions were also on the receiving end of a 7-1 mauling by PSG at the Parc des Princes in 2017. The latest 7-1 drubbing at the hands of Borussia Dortmund in the Signal Iduna Park Stadium saw a third entry into Celtic's European Hall of Shame list under Rodgers.

It is not a new phenomenon for the Celtic fans but it is getting more and more difficult for them to stomach. How can Celtic be unbeaten and imperious domestically but also-rans on their European travels? It was wet and miserable but this wasn't Glasgow's east end it was downtown Dortmund yet the Celtic supporter's spirits were certainly not dampened.

The green and white hordes still have faith and belief that Rodgers can guide their team through qualification and reach the knockout phase.

Tony Haggerty canvassed the views of the Celtic supporters in Dortmund. The burning question on every Celtic supporter's lips right now is: Do Celtic need to adopt a more pragmatic approach in Europe under Rodgers to start achieving results away from home?

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Connor Coyle from Cumbernauld said: "Borussia Dortmund are Champions League finalists from last season so we can't expect much. The 7-1 scoreline is the same old Celtic in Europe, isn't it?

"Celtic need to learn to shut up shop at times. We need to be more pragmatic. I don't think we can play the way we play in Scotland against the quality of the Champions League finalists as they are too good. Celtic came here confident that they could get something as Borussia Dortmund had conceded seven goals in their last two games and the supporters were thinking there was a chance.

"We may be a level above everybody else in Scotland but it is a role reversal in Europe for Celtic, especially in the Champions League. The home games are going to be crucial for Celtic in this league phase now. We need to beat Young Boys and somehow go away from home and beat Zagreb. That will be easier said than done.

"Celtic are heading to Bergamo next to take on last season's Europa League winners Atalanta and we cannot concede seven goals. Under Neil Lennon in the Europa League, Celtic won in Rome and we were unbeaten in that group stage playing pragmatic football. It can be done. We have the players to sit back and play counter-attacking football. Celtic need to stop playing dangerous football against teams who can hurt them.

"The manager tries to play his own style of football in Europe and it is brave but any good coach knows if the template isn't working then it has to be changed. A good coach can adapt and I would never blame Rodgers because he has got us here. Can Celtic still qualify? Absolutely."

Kieran Gowans, Glasgow, said: "We flew from Edinburgh to Amsterdam and then got the bus down to Dortmund. It's been an amazing trip but deflated with the scoreline.

"Celtic are never at their best in Europe away from home, are they? I felt we could have sneaked a draw in Germany. How wrong can you be? It is time that Rodgers started to look at being more pragmatic on our travels and adopting a defensive style. We can always score goals as upfront we can pose anybody a threat.

"Borussia Dortmund and teams of their ilk have players all over the park that can hurt you. We need to stay in games longer. The fans don't want to see a Celtic team shut up shop to speak but we need to be realistic as results like this are a big letdown to those who pay good money to travel and follow the team abroad.

"Celtic can still qualify as our home games are going to be key in this league phase. There is too much pressure and focus on Celtic in away games now. Our away record in the Champions League is terrible and it needs to be improved. Borussia Dortmund are one of the best teams in the world and you can't go toe-to-toe with them. We need to mix up our tactics when we are playing these teams or we'll continue to get punished at this level."

Paul McMullan, Coatbridge, said: "The result is bitterly disappointing as we all went into this game with a bit of confidence. It is amazing what a back-heel assist against St Johnstone can do for the confidence levels, isn't it?

"Celtic were terrible. I would not have given any of the players pass marks. It is all very well saying that Celtic need to be more pragmatic away from home in Europe but what can Rodgers do when his players can't pass a ball? You cannot blame the manager for the players not turning up on the night. We were among the Dortmund fans and they said that it was the best they had played all season.

"It was shocking but Borussia Dortmund played very well. I think most Celtic fans would have said after three games that we would be sitting with three points. I am still confident that Celtic will qualify as I believe that they will win all their home games. They are going to have to.

"Before the Dortmund game, I felt we could get something away from home, I am not as confident about that now. I am disheartened by the 7-1 scoreline but not disheartened by the team. We had confidence but it turned out to be misplaced in the end. We head to Bergamo next to play Atalanta and I still feel we will have three points after three games."

Stevie Crichton, Partick, said: "The pragmatic word is always bandied around whenever Celtic suffer a heavy defeat in Europe.

"That's too many times for my liking under Rodgers that we have lost by a lot of goals. I know the manager said he won't change his approach or style but he is going to have to as the supporters are fed up watching their team getting horsed at this level. It is not good enough for any Celtic team. I watched Steve Clarke's Scotland be defensive against Germany in the Euros and they got hammered as well.

"Borussia Dortmund are a class act granted but Celtic failed to master the basics and a lot of goals were self-inflicted and preventable. The problem with Celtic is whenever they lose a goal they seem to lose two or three in quick succession and they never give themselves a chance to stay in games for long periods.

"Our home games will determine whether we qualify or not. Rodgers has to attempt to do something different when he goes to Bergamo to face Atalanta. All eyes will be on the manager for that match. We keep hearing how lessons will be learned on the European stage from the likes of Rodgers and the players. They will need to show that they have learned something in Italy. If they don't then it could well be another away night to forget in the Champions League for Celtic.

"Conversely, I still think Rodgers will guide the team to the knockout phase on account of our home form."

There is a saying that every day is a school day. On the day after the famous 'Yellow Wall' came face to face with a sea of green and white the Celtic supporters learned a valuable lesson.

It turns out that rock beats water - hands down on this occasion.