It involved 12 games of high intensity and importance. And it finally came to an end in Turin when Juventus brought Celtic's European journey for season 2012/13 to its last stop.
However, the good news for all Hoops fans suffering from Champions League withdrawal symptoms is that the adrenaline rush begins all over again on July 16.
That is when Neil Lennon and his players kick-off the first of three qualifying rounds which can once again see them invited to the top table of world football.
The short time between now and the draw being made on June 24 can be occupied by reflecting on what a magnificent adventure they have been on for the last seven months, and how far it has taken the club, its finances, and of course its reputation.
The foundations were laid last term when what appeared to be a doomed Europa Cup run ignited mid-way through with a victory over Rennes.
The confidence grew, along with the points tally in a group which also contained Udinese and Atletico Madrid.
It was not enough to book Celtic a place in the knockout rounds, but sufficient to imbue belief within Lennon and his lot that they were good enough to make it through to the Champions League.
The addition of players like Mikael Lustig and Efe Ambrose proved very important, and not even the snipes from the likes of Craig "Celtic are out of their depth at this level" Burley or the ITV "bye bye Celtic" sports department could undermine the confidence which Lennon worked hard to instil.
To be fair, not even the former captain could have predicted the twists and turns en route, nor the highlights which included defeating Barcelona and winning in Moscow.
But it was a wise man who said satisfaction is the enemy of all sportsmen, and Lennon was never going to be content with simply qualifying for the group stage.
Though that in itself was a huge achievement, given the timing of the opening ties against HJ Helsinki and Helsingborgs.
The money guaranteed would more than offset the losses the club would have to endure as a result of losing cash-generating ties against Rangers this season.
Without this Champions League income – the Europa League offers only a 12th of this – jobs would have been lost, budgets slashed, sights set lower.
Celtic would not have been the only ones to suffer. At a time when the Rangers ramifications were dragging every aspect of the game in this country lower and lower, the national team was exiting from the race for Rio, and the other would-be Euro entrants were hitting bum notes from their opening lines, the need for some national pride and feel-good factor to be restored was never greater.
By qualifying for the Champions League, then battling through the group stage to the last 16 – something Chelsea and Manchester City failed to do – Celtic put a smile back on the face of Scottish football.
Which is why any suggestion that going out 5-0 on aggregate to Juventus casts a pall over the campaign.
It merely emphasises how unrealistic expectation becomes the further into a competition one of our teams travels.
Consider this timeline. When Celtic qualified for the last 16 by defeating Spartak Moscow 2-1 at Parkhead on December 5, the achievement was lauded around the world.
By the time the draw for the knockout round was made a fortnight later, and Serie A leaders Juventus were paired with the Hoops, the bar had already been raised and the talk was of how it could have been much tougher.
The win over tournament favourites Barcelona in the group stage was used as the barometer of how sunny the future was going to be.
The near-two-month wait for the Juve games to come around simply allowed sense to be given a holiday with realism a faithful travelling companion.
Which is why, by the time the first leg kicked off three weeks ago, the expectation mercury had risen to last eight – and beyond – obliterating the reality which Juve restored with three goals at Parkhead.
The fall back to earth was painful, but inevitable. The important point is how well Celtic pick themselves up, dust themselves down, and prepare to start all over again.
The players and the manager will be better equipped for future years as a result of their Euro trip.
The worry is some of the key components in this unit will not be around when the wheels are set in motion once again in July.
As a result of this Champions League run, the club is on a significantly better financial footing – to the tune of £30million-plus, when gate receipts and bonuses from sponsors are tallied up – from which to repel unwanted bidders.
However, the ambitions of the likes of Victor Wanyama, Gary Hooper, Ambrose and perhaps Fraser Forster may still draw them away.
Celtic can only hope that, having given their stars the chance to play in the Champions League, they will want to hang around for more.
So, Celtic fans should all buckle up and prepare to go again.