Barring a miracle—and we're talking about something major, like Henrik Larsson coming out of retirement, or the entire Juventus squad getting arrested for match-fixing—Celtic won't be going any further than the Round of 16 in this season's Champions League.
Their 3-0 defeat to Juventus in the first leg at Parkhead means that they would now have to win by three goals in Turin, and as well as they've done this season, that just isn't going to happen.
Teams don't go away from home and manage that sort of upset, and teams certainly don't go away to Juventus and overturn a three-goal deficit.
Yet despite this, Celtic can take plenty of positives from their achievements in the Champions League, both in terms of the progress that they've made as a team and the results that they've been able to pull off.
Here are six reasons why Hoops fans shouldn't let this defeat get them down.
The result, in the end, was pretty comfortable for Juventus, and although it would be unfair—not to mention inaccurate—to say that it flattered the Italian champions, Celtic can be relatively pleased with the way that they performed.
They held onto the ball for large periods of the game, getting a roughly equal share of possession, and while they were unable to break down a well-organised defence, they did at times look threatening.
The fact that the game finished 3-0 says a lot more about the qualities of Juventus as a team than it does about Celtic's deficiencies, even if it does suggest that they still lack just that bit of quality that might see them compete at this level.
Even if Celtic had failed to qualify from the group stages this season, and even if they'd failed to get a point from any of their other games, this season's campaign would still go down in history as the season that they beat Barcelona.
Thought by many to be the greatest club side ever assembled and featuring arguably the best player of all time, Lionel Messi, Barcelona were humbled at Parkhead back in November by a Celtic side that refused to listen to the doubters who dismissed them as having little or no chance of getting a result.
Barcelona dominated the game, having 73 percent of possession, but as any Celtic fan will tell you, it's the result that matters, and this result mattered more than most.
As a result of their achievements on the park, Celtic's Champions League run has been highly beneficial for the club's finances.
Taking into account sponsorship money, participation money, match fees, television money and performance bonuses, Celtic will have made something in the region of £20 million from this season's competition, which will go some way towards improving their overall financial situation.
In football today, money is everything, and the only way that a team can hope to compete with the very best is to be able to compete with them on a financial level—and that means qualifying for the Champions League on a regular basis.
If Celtic can make this a habit, then it can only mean good things for their stature as a club, and it will improve the calibre of players that they're able to attract.
In Celtic's previous forays into the Champions League, one aspect that had always let them down was their poor form away from home.
Even in the years in which they were able to make it past the group stage, they did so because of their excellent home form, and there was always the feeling that their inability to travel well was holding them back.
This season has shown the great strides that they're making towards improving this.
The away legs of their qualifying ties that they made look routine, and they carried this over into the group stage with an impressive 3-2 win away to Spartak in Moscow.
An impressive performance at the Nou Camp followed, and while they might have been disappointed with how things turned out in Lisbon, the signs are there that they are over their problem of going away from home in the Champions League.
When you compare the performances of many of the Celtic players in last season's Europa League games with their performances in the Champions League this season, you'll notice a marked improvement.
Fraser Forster has emerged as one of the best young keepers on the continent, pulling off an incredible number of saves during the group stages and keeping some of Europe's best attackers at bay.
Victor Wanyama has also been attracting the attention of Europe's elite clubs, and Celtic might find it difficult to prevent their star midfielder from leaving come the summer.
But it's not just the big names that have shown their worth.
Throughout the squad, Celtic's players have proven that they're now able to compete in the Champions League, looking much more comfortable on the ball and demonstrating a tactical nous which they had often previously lacked.
The Celtic coach has come in for a fair bit of criticism following his decision to play Efe Ambrose against Juventus, with the player having only just returned from the African Nations Cup with Nigeria.
As we saw, it's the sort of mistake that can prove costly to a side, but it is just that, a mistake, and Lennon will know now not to do the same sort of thing in the future.
At just 41, Lennon is still a young manager and is learning and improving all the time.
He'll have gained a lot from this season's campaign, developing his own tactical approach to the game and watching some esteemed adversaries in the opposition dugout.
He'll come back even better prepared by the time that next season's Champions League comes around.