European qualifiers require strong stomachs.

A 3-1 lead and a commanding display in which they hit the woodwork three times last week ought to have suggested a relatively straightforward passage into the third qualification round, but these occasions appear to demand drama and tension.

Rosenborg put Celtic’s makeshift defence under pressure from the early stages and it was a game, in the opening half particularly, best viewed through the cracks of fingers at times from the perspective of the Parkhead side.

Had Craig Gordon not produced an impressive save to tip over a header from Marius Lundemo just on the cusp of the break it could have made for particularly queasy viewing.

Read more: Brendan Rodgers hails Kris Ajer and Jack Hendry as Celtic withstand Rosenborg barrage to progress in Champions League​

Craig Gordon has still got it.

The goalkeeper’s save that denied Lundemo was vital, particularly given its timing. The concession of a goal at the end of an opening half that Celtic had toiled in would have allowed Rosenborg to scent blood. Between that and his block from Jonathan Levi’s effort, Gordon had a decent say on ensuring that Brendan Rodgers’ side progressed to the third qualifying round. Blotted his copybook a little when he flapped at one effort but Nicklas Bendtner’s elbow ensured it mattered little as the striker was penalised for a foul.

Odsonne Edouard will hog the headlines for Celtic this season.

The French striker found it tough to get into the game and was isolated for much of the time he was on the field but he offered a reminder of what he has with a fine run just after the break. After pushing into Rosenborg’s box and shrugging off a defender with a nifty stepover he was unlucky just to curl his effort wide of the target.

Read more: Brendan Rodgers hails Kris Ajer and Jack Hendry as Celtic withstand Rosenborg barrage to progress in Champions League​

It is not entirely fair to suggest that we only learned last night that Celtic’s defence is their achilles heel.

In fairness, in Jack Hendry and Kristoffer Ajer Celtic had an inexperienced and youthful combination at the heart of defence for the simple reason that it was a case of needs must. Ajer’s maturation into the role has been notable and in fairness to Hendry he grew in confidence as the game went on. Ultimately, though, these games are simply about survival and making in through. Mikael Lustig will be expected to be back for the game against AEK Athens but further cover defensively would not go amiss.

Someone in the New Balance marketing office has a magpie’s eye for the bright things.

Celtic luminous pink goalkeeper’s away kit coupled with the bumblebee colours of the outfield players is not a pretty combination.