CELTIC’S European record this season makes a mockery of the notion that preparation is key to success. Before every game Ronny Deila has laid out what he expects his players to do, where they need to be strong, what they need to watch out for, the pitfalls and the opportunities. And yet, come the night itself, they have still repeatedly found themselves undone by some unforeseen calamity or other. It is like getting the Queen’s private secretary to meticulously plan the details of your holiday abroad and then letting Mr Bean take charge when you get there. The chaos that follows is as inevitable as it is frustrating.

There is little room for error now. When Ajax come to Celtic Park this Thursday Deila does not need players getting sent off for daft tackles or defenders making spectacular howlers. Rock bottom of Europa League Group A and without a win after four games, Celtic are entering last chance saloon territory. The arithmetic tells you they do not definitely have to beat Ajax to retain any chance of reaching the knock-out phase but Deila wants to remove the need for fiddling about on his calculator come the night. “We have to win”, acknowledges the Norwegian. “But even 1-0 will be enough.”

The latter part may be harder to achieve than the former. Celtic have not kept a clean sheet in their last 10 Europa League ties, and conceded at least twice in each of their last six European games. On the plus side they have been scoring regularly themselves making something like a 3-2 or 4-3 victory, against an Ajax side who have hardly been rock solid at the back themselves, seem a more realistic aspiration. Throw in the fact that his defence comprises an ever-changing cast, and that two of the players who could offer midfield protection – Nir Bitton and Stefan Johansen – are both suspended, then it looks an even bigger ask.

Perhaps the team, knowing they have to win and spurred on by an expectant home crowd, will abandon all tactical discipline and decide just to lay siege on the Ajax goal and see what it brings. That is not what Deila wants at this juncture, although, when it comes to Europe, his best-laid plans rarely turn out as hoped for.

“It starts with good defending,” he added. “We have to be a unit with a lot of energy and belief, but we also have to be patient. We have to show aggression and the tempo that we need to get into these games. We are at Celtic Park and we are going to be kings. That’s what we want to do. We just have to do our tasks, do everything right every day and enjoy it and if we do that everything will be fine. But you can’t just go out and try to blow them off the pitch. The other teams can play football, too. So it is about defending well which is the most important thing.”

Deila dreams about taking Celtic to the group stage of the Champions League although, at the moment, that seems quite a long way off. How he fares in the next two Europa League ties against Ajax and Fenerbahce, and whether he can somehow steer the team into the last 32, will likely go a long way in deciding whether he gets another crack at it next summer or not.

He admits he is consumed by a desperation to do well in Europe although, paradoxically, wonders whether he and his players stress too much about it.

“I’m more disappointed than angry,” he says of recent results. “You feel that you have something to prove and you really want it. It’s those small details that either go the right way or the wrong way. But it’s so big as well so you need to get these things right. There is nothing I want more than to play in the Champions League with Celtic. That’s a big, big goal. And I know everyone wants it so badly. Maybe sometimes we want it too much.”

Failure to beat Ajax on Thursday would likely consign Celtic to a season of domestic chores but, perhaps in response to the inevitable backlash that will come his way if such a scenario unfolds, Deila believes even the most humdrum victories are worth celebrating. Even the Ronny Roar might return.

“Every time you win games you have to enjoy it. You shouldn’t just win things and think, “well, that’s how it should be”. Yes, maybe we should beat every team here in Scotland but you have to enjoy it when you do it as it’s possible to lose games. Be happy when things are positive and enjoy it. Don’t always react when things are negative. It should be fun to win. That’s what I have to do more. I have to enjoy winning even more – and the players too – as not everyone else does that, winning all the time. Domestically we have lost one game and are still in everything. So we need to enjoy that more.” Winning in Europe, though, is what he wants most of all.