It is difficult to quantify the magnitude of this week for Celtic.

Two days to go and that which defines the season, that which has been in soft focus since the end of last term looms into sharp distinction. The first leg, conclusive play-off leg against Astana cannot be couched in anything other than hyperbole; it is the game that adds a layer of glamour and prestige to Celtic’s season – not to mention the minimum £25m windfall that encourages the forward momentum in all areas of the club - or it is a tie that punctures the soaring spirit of the club that was so emphatically established in the opening season of Brendan Rodgers’ campaign.

Leigh Griffiths has been the man in the spotlight this weekend following the news that those troublesome calves have been at it again. The striker got a bit of game time at Firhill on Friday night but the original plan to have him chomping at the bit after another 90 minutes did not materialise.

It means that he goes into the game against Astana as the lead striker without being fully at it – Moussa Dembele being out until after the international break at the earliest – but the forward is comfortable with the pressure that lies on his shoulders.

“I’ve said all along that I want to earn that jersey,” said Griffiths. “It is a bit frustrating because I came back really fit after the break, I did loads of work over the summer and I have worked with the physios so it was annoying but hopefully it is just a blip.

“It will be a hard game. We know that from last year. They gave us a really tough test and I think it will be the same again but it is up to us to prove that we belong in the Champions League. We’re under no illusions. It will hard but we feel confident.

“We will be prepared and I think we are a different team now to what we were 12 months ago. It won’t be easy but we have built up all summer looking to get ourselves back in the Champions League and that is what we need now, one last big push.

“We think we have the quality to get through.”

Astana’s stats at this stage in the competition may make for grim reading for Celtic. The Kazakhstani side are unbeaten across 14 European home games, although Celtic will take some assurance that there have been eight draws in amongst that. However, they have lost only once on their hybrid surface in a run that spans nearly 12 months.

The suggestion, then, is that Celtic badly need to board the plane for that eight-hour journey next week with the comfort of a significant cushion from Wednesday’s opening leg, with a two-goal advantage offering complete control of the second leg.

Griffiths, though, was quick to point out that Celtic coped with a disappointing opening game draw with Rosenborg before progressing with a positive win in Trondheim.

“We won’t go into the game thinking that we need to get x, y or z,” said Griffiths. “Of course, we’ll be going out to win the game as we always do.

“We want to give a strong account of ourselves but we won’t be gung-ho or anything like. We’ll be calm and focussed, play the way we always do and trust ourselves to get the result. I think we have seen already with the Rosenborg game that we can go away from home and get a result.

“We need to remember that it is a two-legged tie. We want to play as well as we can and do our job over the two legs and if we do that then hopefully the quality that we have got will shade it.”

Last season it was a last gasp penalty from Moussa Dembele that sent Celtic past Astana, with very little between the teams.

Astana are a little different to that side, although not hugely. Their creative playmaker Azat Nurgaliyev has gone as has one of the scores at Celtic Park, Agim Ibraimi.

However, the strike pairing of Ghanaian forward Patrick Twumasi and Congo international Junior Kabananga have gathered growing interest given their prolific partnership for the Kazakhstan side.

The Astana hierarchy publicly insisted that they would not sell either player before the Champions League qualifier against Celtic, a move that came following Twumasi trying to steer a move to Bursaspor. Between them, Twumasi and Kabananga have bagged 11 of Astana’s last 17. Kabananga, too, was top scorer in this year’s Africa Cup of Nations.

However, Griffiths was right to point out that the momentum from last season has carried Celtic into such a position that they can be trusted not to take a nose-bleed at this pivotal stage of the competition.

“We want to continue from last season. There is a confidence and a belief about us and I think that is huge when you are going into games of this magnitude.

“We trust ourselves, we trust those around us. We know that if we go out and play to our capabilities then we will get the result. There is pressure but there is always pressure here. We just need to ignore that and focus on the game.

“We can’t look at anything other than ourselves and how we play, how we go about it. We have belief but we have that belief because of the way we have been capable of playing.”