Those at Celtic who know their recent European history will not be counting their chickens but the Champions League draw, and the schedule of fixtures, have given Brendan Rodgers’ side a glorious opportunity to begin this tournament with a bang for a change.

It is a chance they dare not miss. In their own place, Celtic should be too good for Slovan.

The form of Rodgers’ team is encouraging. They are playing at a higher tempo than last season, their pressing game, work-rate and creativity look good. They have signed well. They have a bit of a strut about them.

The caveat is we are judging them on domestic form, a barometer that has blown up in everybody’s face in the past.

Are Celtic more than mere flat-track bullies? We are about to get some answers in Europe. This is their testing ground, not Scotland where they are odds-on to skate away with the Premiership. The Champions League will show Celtic’s worth and indeed, Rodgers’ worth.

With his domestic dominance he has written his name into the fabric of the club but Rodgers’ record with Celtic in Europe is poor. He’s been manager in 18 Champions League group games, winning two, losing 12 and drawing four.

His team has scored 15 goals with 49 conceded. In among that lot, there are 5-0, 6-0, 7-0 and 7-1 defeats. The strange paradox is that many of the worst European results in Celtic’s history have come under one of their most convincing leaders.

When you include Europa League games, Rodgers’ European record at Celtic is six won, 18 lost and four drawn (of the 28 played). Rodgers has mentioned his desire to improve on that. Deep down you sense it is not just a wish but a raging ambition to make Celtic relevant in Europe again.

Until they do something about it, their failures will be thrown in their face. There were many matches nobody expected Celtic to win but there are others they could have won but did not, for various reasons.

These are the lessons they must learn for this campaign. Discipline, concentration, ruthlessness. Discover their inner dog. A rottweiler rather than a poodle.