For all that Celtic are commemorating the club's past, new glories can still be achieved. Neil Lennon held his head in his hands at the final whistle, because the joy, the sheer unadulterated jubilation, could not be contained. So much of the night will remain in the collective memories of Celtic fans, a reminder that the game, for all its simplicities, can provide moments of triumph that are overwhelming.
The occasion was immediately ecstatic. Some thoughtful deliberation went into the card display that greeted the teams as they came on to the field, but the over-riding sense was of an uncontrollable surge of emotion. The noise was unbound, and it carried power enough to move the spirit. At a time when Celtic are celebrating the 125th anniversary of the club's foundation, supporters are conscious of the great sweep of history that lies behind an evening like this.
The Champions League is a reward for the patient development of Lennon's side, and the steady accumulation of nous and prizes. Yet this was, too, a reward for the supporters' endless commitment. An occasion for the ages, there was a tumultuous spirit that the stadium could barely hold.
Boldness was evident in every aspect of the contest, since Barcelona fielded their strongest team, and Lennon, in response, was prepared to line up with two strikers in Georgios Samaras and Miku. There were subtleties to that formation, with Miku dropping deep whenever Barcelona attacked and Samaras stretching the play by staying high up the pitch, and the shape provided the Celtic defenders with two out balls: short to Miku, or long to Samaras.
Lennon must have agitated over every connotation. Miku had impressed only in brief flashes since joining the club at the end of the transfer window, while Tony Watt, the bullish young striker, has performed with raw but persuasive ability this season. The Celtic manager could only be restless, since his instinct is to be involved in every passage of the game. He was a constant presence on the touchline, mentally engrossed in the small details of the game. Tito Vilanova, in contrast, seldom emerged from the Barcelona dug-out.
Discipline epitomised Celtic's display, though. Kris Commons and Charlie Mulgrew were stationed on the flanks rather than exploiting them, and they often dropped into the full-back positions, with Mikael Lustig and Adam Matthews tucking into the centre, when Barcelona moved the ball towards the Celtic penalty area. That kind of ordered thinking was fundamental to Celtic's hopes, but the threat to Barcelona was contained in the unpredictable moments.
Victor Wanyama could brush opponents aside in midfield, since his power and athleticism was too forceful to be restrained. The impression was of a figure Barcelona accepted they could not conquer. The visitors could dominate possession – although to a lesser extent than they did at Camp Nou – but their vulnerabilities could not be disguised. Celtic were adamant that they could exploit set-pieces, and the stadium responded with a ferocious yell when the home side won a corner in the 20th minute.
Elite players tend to be immune to the convulsions of the crowd, but Barcelona were still exposed. Jordi Alba was marking Wanyama at the corner kick, but was brushed aside by the midfielder's driving intent. His header flew past Victor Valdes and the noise that erupted around Celtic Park was a furious expression of delight. It subsided to a precious sense of hope, since the visitors had seen much of the ball but created little danger. The challenge for Celtic, then, was to contain themselves. As the game at the Camp Nou emphasised, Barcelona are not perturbed by falling behind, since their style of play is so ingrained that it is unshaken by the individual dramas of a game.
It must have seemed inevitable to them that a series of passes would end with an Alexis Sanchez effort on goal, but the striker's careful header bounced off a post. There could be no respite for Celtic, since a single pass from Xavi could still almost undo their good work; it sent Dani Alves through, but the full-back could not quite reach the ball to control it. Celtic could never allow themselves to be distracted. They also could not muster so much adventure in the second-half, as Barcelona established a holding pattern in the final third, where they kept trying to pick their way through the home side's defence.
Every Celtic player had to be impeccable, and Fraser Forster made an outstanding save from Lionel Messi after a spell of patient passing ended with a fierce strike by the Argentine. Celtic might have felt, then, as though they could only protect their advantage, and the diligence of Commons, who performed with responsibility and consideration throughout, was emblematic of Celtic's discipline. Yet they could still be brazen.
When Xavi missed a through ball, Watt could not be disrupted as he surged through to drive a low, hard and emphatic shot beyond Valdes. At that moment, as Lennon celebrated with his staff and substitutes, every glorious ambition must have seemed possible. That sentiment survived Messi's late consolation goal since the night, in all of its triumphant possibilities, belonged to Celtic.