Speaking in the Scottish Daily Record, Messi said:
"They were very lucky. It’s a shame but we just couldn’t do anything about it. We did everything in the game but just couldn’t get past them. Celtic came at us twice and got two goals from it. When they scored they just locked their defence. The first goal from the corner arrived because they are a bigger team than us – it was the same as their goal in the Nou Camp. The second goal was our own fault."
Someone needs to explain to Messi what "luck" actually is. It is defined on merriam-webster.com thus:
"to prosper or succeed especially through chance or good fortune"
Was it chance or good fortune that in the 21st minute Charlie Mulgrew hit a perfect corner kick to the back post for Victor Wanyama to head home?
As Celtic manager Neil Lennon revealed after the match:
"We looked at their back-post area with (Jordi) Alba in the zonal system and Charlie Mulgrew is one of the best dead-ball players around."
Lennon and his backroom team didn't just put out 11 players and hope for the best.
They had been carefully planning their tactics for weeks beforehand and identified that Barca's zonal marking system at corner kicks isolates Jordi Alba at the far post.
The goal came straight from the training ground and was perfectly executed.
How about Celtic's second goal?
Well, Messi may be right about that; it was their own fault.
Xavi Hernandez badly misjudged a long clearance from goalkeeper Fraser Forster and this allowed the ball to bounce nicely into the path of 18-year-old substitute Tony Watt.
Was that bad luck, or was it a rare instance of poor technique from the normally impeccable Xavi?
Watt still had lots to do when he took possession.
Javier Mascherano was in close attendance, so was it luck that Watt was able to comprehensively outpace him and dispatch a cool finish past Victor Valdes?
Or was it a reward for Lennon's boldness in replacing full back Mikael Lustig with the young striker?
Was it simply the result of a direct, pacey forward picking up the ball in a dangerous area, and doing what he does best?
Perhaps Messi's opinion is predicated upon the match stats, which showed the balance of play overwhelmingly in Barcelona's favour.
Barca had 72 percent of possession, and 24 shots on goal with 14 on target.
Against this, Celtic had 28 percent of possession and five shots on goal with five on target.
If you crunch those numbers a little, you find that Barcelona hit the target with 58.3 percent of their shots, while Celtic were on target with 80 percent of theirs.
Barca scored with 4.2 percent of their shots, while Celtic scored with 40 percent of theirs.
Barcelona had the ball for around 65 minutes of the 90, Celtic for around 25 minutes.
That looks to me like Celtic's unheralded team were much more efficient at converting possession into chances, and chances into goals than the Catalan superstars were on the night.
Of course, Barcelona's players are of a far higher standard technically than Celtic's.
Cesc Fabregas cost about six times more than the entire Celtic team on Wednesday night, and he didn't even make the starting line-up.
Barcelona play beautiful soccer. Their passing and movement off the ball are sublime.
They press like furies when they lose the ball.
All of which combines to ensure they enjoy the vast bulk of possession in every game they play.
When you play against Barcelona, you know you won't see much of the ball.
What Neil Lennon did on Wednesday was find a way to beat them.
Following Chelsea's example, Celtic ceded territory and possession and ensured they defended their penalty box.
This meant pulling the fullbacks—Mikael Lustig and Adam Matthews—inside the box, also ceding the flanks to Barcelona, although both had to ensure Alba and Dani Alves were never allowed to run unimpeded into the box.
Matthews in particular was outstanding, especially so given he was playing in the left-back position.
Efe Ambrose has very quickly established himself as a solid addition to the centre of Celtic's defence, but almost unnoticed, Kelvin Wilson has transformed his fortunes at the club alongside him.
Almost sold to Ipswich Town for £250,000 in the summer, Wilson has now made himself a fixture in the starting line-up.
Ambrose and Wilson formed a defensive wall that proved almost impossible for Barcelona to breach.
In front of the defence, Victor Wanyama and Joe Ledley ensured that Barca's midfield were rarely able to pass their way through to goal.
Ledley barely touched the ball but his non-stop running and covering meant that Xavi and Andres Iniesta were never able to settle on the ball in advanced areas, where they can cut the best defences open.
Wanyama was simply immense. Barca just couldn't find a way past him. He constantly broke up attacks, sometimes just by his sheer presence, and he proved adept enough in possession to hold the ball and pass intelligently.
The Kenyan powerhouse of course also scored that crucial first goal. As directed by Lennon beforehand, he loitered just outside the box as Mulgrew lined up the corner kick, and he easily out-jumped the isolated Alba at the far post.
Just a shame he had the poor manners to be bigger than the diminutive Spanish international.
Whenever Barcelona did find a way through the defence, they found goalkeeper Forster virtually unbeatable.
Again there was no luck involved. Forster has developed into a tremendous shot-stopper and fully deserves his recent England call-ups.
Celtic were disciplined and diligent throughout and restricted Barcelona to very few clear-cut chances.
There is an art to defending as a team. It may not be as exciting to watch as Barcelona's pin-ball passing and possession play, but it is every bit as much part of the game.
Celtic defended superbly well, and luck had nothing to do with it.
If one side did enjoy some good fortune on the night, it was actually Barcelona themselves.
After picking up an early booking, Alex Song was extremely fortunate not to find himself ordered off before half-time with a cynical block on Miku Fedor to prevent a Celtic breakaway.
Then midway through the second half, he fouled Miku again, this time from behind and leaving the Venezuelan forward in a crumpled heap.
Referee Bjorn Kuipers elected to keep the red card in his pocket again.
There is also a case to be made that Mascherano should have been red-carded for a foul on Watt as he bore down on goal in the final minutes with the score 2-0.
Barca could easily have finished the match with only nine players.
This is not the first time in UEFA competition Kuipers has appeared to favour Barca.
I love watching Barcelona. In my opinion they are the best team in the world. In Xavi, Iniesta and Messi, they have three of the best players in the world. They are almost untouchable.
Why then, do they have to complain every time they are beaten, that the other team has refused to play into their hands and allow them the run of the pitch?
What are teams like Celtic supposed to do when they play Barca?
So they only had 28 percent possession. That's because Barca keep possession so well and hound the opposition relentlessly when they lose it.
So they defended grimly. Are they supposed to stand back and admire Barca?
Since organized soccer began in the 19th century, strategic and tactical innovation has been followed by measures to counter them.
Barca need to accept that their tika taka play, of which they are justifiably proud, will inevitably be countered. That is the lesson of soccer history.
They need to stop accusing other teams of bad sportsmanship for having the temerity to use physically bigger players than them and defend well, and consider their own faults.
One of which is a curious reluctance to shoot at goal from any further than 18 yards out, preferring instead to weave pretty patterns in an attempt to virtually walk the ball into the net.
They might start by considering that possession is a means to an end, not the end itself.
On Wednesday night, Celtic were not lucky.
They defended better than Barcelona did, and they attacked better than Barcelona did.
That's why they won.
Follow Daniel O'Connell on twitter @DanielOConnel18