But it is not simply the financial disparity between Uefa’s elite tournament, from which Celtic raked in more than £20 million last season, and the Europa League, where even a run to the semi-finals earns just £5m, that so intensely motivates the Scottish champions.
As they seek to overturn their 2-0 first-leg deficit against Shakhter Karagandy in the play-off round tie, Neil Lennon’s players are on a mission to both avoid a severe dose of ignominy and ensure the rest of their season has genuine meaning and prestige.
The anger being expressed at their Lennoxtown training ground yesterday is only partly directed at a Shakhter side they feel have shown them a lack of respect in the wake of last week’s match in Kazakhstan.
Celtic are also angry with themselves for getting into a situation where their place among the glitterati of European football is threatened by the lowest-ranked side left in the tournament. Even Georgios Samaras, unquestionably the most laid-back of Lennon’s squad, has been worked up into something approaching a frenzy.
“I don’t remember ever being this angry going into a game,” said the Greek forward. “Not angry as in going to kick people, but angry because it’s a game I want a lot. It is one of these games that you cannot lose. You want to win and win well, want it with everything.
“With Celtic, you win titles, you win games, it feels normal sometimes. You go to a game, you play it, you win it – and you know you’re going to win. This is different. It’s the whole season for us. And I don’t want a team from Kazakhstan to ruin that for us.
“The anger that I had at the end of the first leg, I will take a lot of that with me on to the field this time. This is a game that is for our club, our team-mates, our careers.
“To be back in the group stages of the Champions League and create those great nights this year, it’s what we want. We enjoyed those Champions League nights so much last year and will do everything to get back there.
“The Europa League is different, no doubt. They are different nights here. I’ve played both, Europa League nights at Celtic Park and Champions League nights at Celtic Park. They are totally different.
“It was hard to accept the result in Kazakhstan. If you play against a better team than you and you don’t have the quality, that’s one thing. You are going to lose some of those games.
“But this was not one of those games. It was a game we shouldn’t have lost. It doesn’t matter, though, what I say about how we felt, whether we could even believe that we’d lost. The result won’t change, it’s 2-0 and we need to score three goals.
“The only thing I can say is that we know we are a better team. We fully respect them but we know that, at Celtic Park, with our fans behind us, we can do this.”
Samaras has previous experience of overcoming a 2-0 first leg loss in Europe, having scored Heerenveen’s first goal to spark a 5-0 second leg comeback against Czech side Banik Ostrava in the Uefa Cup eight years ago.
But he will cast his mind back to a more recent event, when he was on the wrong end of such a scenario, as a more pertinent reminder of how these ties can be turned on their head. In the Europa League play-off round in 2010, Samaras scored to give Celtic a 2-0 first-leg advantage over Utrecht, only to be blown away 4-0 in the return fixture in the Netherlands.
“I have tried to forget a lot about that game,” he added. “But I do remember that Utrecht scored early and we were suddenly insecure about everything in our game.
“That is what we will try to do to Shakhter tomorrow. I think, if we score an early goal, anything can happen.
“When I say an early goal, I mean any time in the first half. It is psychology, if we get one goal up at half-time, the second half will bring a lot of pressure on them, we can attack more and more.
“Sometimes football is about mind games. Before the game starts, maybe they have confidence, think about defending well and keeping a clean sheet.
“If we score a goal, the mentality before the game, all the approach to the game, changes immediately.
“The plan to keep a clean sheet is gone. Then you need to stay strong and focused on a game. That’s difficult.
“That’s why we approach the game like we approach so many games here. We know we’re going to have a lot of the ball, we know we’re going to create chances. It’s up to us to score the goals.”
Avoiding the cheap concession of goals will also be imperative for Celtic if they are to book their place in tomorrow’s Champions League group stage draw. Samaras is confident the defensive frailty that was conspicuous in their defeat in Kazakhstan and again in their Scottish Premiership draw at home to Inverness on Saturday will be addressed.
“The goals we lost in the first leg were the first we have conceded in five European games this season,” he said. “I have full confidence in our team and in the back four. We believe in our ability. We are more confident than the fans. We have the quality to do it.”