This was the latter for Neil Lennon.
With it looking as though Neil Lennon was on the verge of enjoying his proudest moment as a manager, he found himself suffering the most agonising end to a game imaginable as his team lost in the Nou Camp with literally seconds to spare.
It appeared as though an inspired performance from the SPL champions was going to produce a shock result away to Barcelona. The 90 minutes had come and gone with the scoreline locked at 1-1 as Celtic moved to within touching distance of a famous result.
There were four minutes of injury-time to get through before they could celebrate the incredible achievement of sharing the spoils with the world's most impressive football team. When three of them had expired, the final whistle was just seconds away.
Then, out of nowhere, Barca broke Lennon's heart by netting with almost the last kick of the match as Jordi Alba bundled the ball over the line to hand his side a 2-1 victory. Instead of leaving the field having recorded a famous result, the players left dejected at having it snatched away at the last gap.
But when the dust settles and the adrenaline begins to stop pumping, The Celtic boss and his players have every right to be extremely proud of their efforts in Spain.
The Hoops boss spoke of not wanting to see his young team embarrassed at the expense of the Catalan giants, and his pre-match fears were fully justified considering some of the best sides in Europe have taken on the Spanish side on their own turf and not lived to tell the tale afterwards.
As much as he has confidence in the team he has assembled, Lennon was not to know how they would handle the toughest test they are ever likely to face. He hoped they wouldn't be crushed and demanded they play the team rather than the jersey.
Deep down, however, he was not so sure. No manager can be – not when they are sending their team out to face the likes of Lionel Messi, Andres Iniesta and Xavi.
He shouldn't have worried though. His team more than did him proud, despite losing the game in the 93rd minute.
Not content with starting the group with an impressive scoreless draw at home to Benfica before following it up with their first away victory in the Champions League away to Spartak Moscow, the Parkhead manager set his team up in a surprisingly more adventurous line-up than many expected.
Gary Hooper started in attack with Georgios Samaras also up top. A midfield four backed them up in front of a flat back four and, as much as they were forced to defend for large periods of the game, Lennon made it clear they didn't come to Spain to defend in numbers from start to finish.
And do you know something, no-one could begrudge Celtic's players a share of the spoils had they held out. Yes, Barca did enjoy the vast majority of possession. They always do. And, yes, Fraser Forster had to have the game of his life – which he did. But the only thing missing on the night was luck in the closing moments.
It would have been a result which would have made the rest of Europe stand up and take notice.
Scottish football has been battered from pillar to post in the last year, but what Celtic have achieved already this term in Europe has more than repaired that reputation.
Even in defeat, their overall display in Spain won't have gone unnoticed around the continent.
Perhaps against the run of play, Celtic managed to take the lead inside the Nou Camp when a Charlie Mulgrew free-kick caused Barcelona problems and Samaras' header cannoned off Javier Mascherano and into the back of his own net. Even the Celtic players looked amazed as they raced away to celebrate.
However, just when it looked as though the Scottish side's confidence levels had increased significantly as a result of taking the lead – they were retaining a better level of possession while putting it to good use – Lennon was forced to alter the his team when Samaras was forced to limp off with an ankle injury.
Hugely influential in the way the SPL champions line-up in European fixtures, the loss of the Greek Euro talismanwho provides them with the option of going from back-to-front was always going to be to their detrimen.
And so it proved. Just before they could make it into the dressing room at half-time, the home team found an equalising goal through Iniesta.
If that was a bitter pill to swallow, worse was to come at the end of the second-half when Barca left it even later to find the winner.
It could have been a point of great significance in terms of qualification for the knockout stage of the competition. But, if there is such a thing as pride in defeat, then this was it.