Neil Lennon traces it back to the Stadio Friuli, at least in spirit.
There were many contributing factors to Celtic's victory away to Spartak Moscow in the Champions League last week, and the manager could enthuse about each of them with relish, but the origins of the result are found in a 1-1 draw in Italy. That Europa League tie against Udinese last December convinced Lennon his side would not always be neurotic about away games in Europe, or vulnerable to self-doubt.
Lennon's inclination has been to praise individuals. He raved about Gary Hooper's display in the lone striker's role, the hard-running and competitive zeal of Scott Brown, Georgios Samaras's languid aplomb and the raiding ambition of Emilio Izaguirre up the left flank. It was the collective response to the circumstances of the game in Moscow that was critical, though, the sense that the tie had not been discarded as Celtic fell 2-1 behind, or that Spartak's defensive approach after being reduced to 10 men could not be overcome. If the victory could be reduced to a single component, it would be belief.
"It's all about the players," Lennon said, and of course so much of the vital resolve was generated among significant performers. Yet the result belonged almost wholly to the manager. The draw with Udinese, which he identified as such a key moment in his team's evolution, was itself a product of Lennon's insistence that the team improve over the course of a group campaign, that every game was a chance to reclaim some esteem on the continent.
Only six of the players who started that night in Italy were in the starting XI last Tuesday, though. If the nurturing of Hooper's talent, the constant championing of Brown and Samaras, the careful attention to the defenders, even the personal development of Charlie Mulgrew, are all aspects of Lennon's management, the critical quality seems to be an ability to set standards of application, commitment and adventure to a squad that has been pieced together by the club's scouting staff.
Yet the psychology of converting individual personalities to a single cause is just as significant. Of all the evidence that suggests Lennon could become a formidable manager, it is the man-management of his players that already appears critical.
"I was hoping that would be a game-changer," Lennon said of the Udinese encounter. "That's the one game that sticks out for me from last season and I'm not just talking about Europe. We also created chances against a good side. It gave me a lot of encouragement. The performances from last year gave them a taste and an appetite. I was sitting there at 2-2 on Tuesday, Spartak are down to 10 men and thinking 'please don't have one of those horrible moments or concede in the last minute'. But the way the players controlled the last 20 minutes was good. You make the substitutions and lose the game 3-2 and you're naive for being too gung-ho. You win and you're a tactical genius and all that rubbish."
Lennon had dinner on Friday night with Dermot Desmond, Celtic's majority shareholder, to talk about the development of the team and the club. Other clubs will have taken notice of Celtic's achievements in the last six months, particularly since the club operate on a budget that is modest compared to that of most leading sides in Europe, most notably in England.
It has been an advance based on shrewdness, since Celtic are restricted to markets that offer value for money or are under-used. That demands more of the manager, who has to overcome the rough edges or flaws, and Lennon is currently revealing a clever awareness of the strengths and weaknesses of his players and how they ought to be deployed or minimised in his team. It is this passionate and questioning nature that Desmond identified as among Lennon's own defining qualities.
The players are responding, and Lennon is in turn to them. Talks are ongoing with Hooper about a contract extension, but new deals were agreed with Mulgrew, Adam Matthews and James Forrest on Friday. Each has been rewarded for their own improvements, but also that of the team, which was a ploy Martin O'Neill used with his players – including Lennon – to ensure that they would not become complacent or restless.
Management becomes about compromise as much as ideals, and Lennon must cope with the ongoing saga of Brown's fitness. The captain will not face Hearts today, while he nurses a sore hip, but the team cannot concede any ground, at least to their own high standards. "I felt we could compete in this [Champions League] group, but we have already played better than I thought we would," Lennon said. "It's given me a lot of satisfaction and the players a lot of belief."