Celtic came oh so close to snatching a precious point in the Nou Camp tonight, losing out on a last-gasp goal from Jordi Alba 30 seconds from the end.
The pattern of the match was fairly predictable beforehand, with Barca enjoying more than 70 percent of the possession, and attacking at will.
Despite their dominance though, Barcelona found it very difficult to open up a stubborn and dogged Celtic defence, with Efe Ambrose and Kelvin Wilson in tremendous form.
The defence was well protected by Victor Wanyama and Scott Brown and for much of the match Barcelona were forced to play in front of that formidable banner.
Celtic was in dreamland in the 17th minute when Scott Brown was fouled on the right wing and Charlie Mulgrew whipped a dangerous cross into the box from the free kick.
The ball landed perfectly for Georgios Samaras and his header deflected off Javier Mascherano and into the net to give Celtic an unlikely lead.
The play followed the same pattern for the remainder of the half, with Barcelona constantly threatening, but never really carving out a clear opportunity, until the 44th minute.
That was when Barcelona finally clicked and Messi combined with Iniesta for the latter to stab the ball beyond Fraser Forster despite the close attention of four Celtic defenders.
It was desperately unfortunate for Celtic to concede so late in the half, having defended superbly for so long, especially after the huge blow of losing Samaras on the 39th minute after he went over on his ankle.
The second half followed an identical pattern of increasingly threatening Barcelona attacks, with Forster having a brilliant match, making two breathtaking saves on Lionel Messi.
First on a 67th minute low cross from the right, the Argentinian met the ball on the edge of the six yard box and Forster showed incredible reflexes to bat away his snapshot.
Forster possibly bettered that in the 74th minute when Messi’s late run into the box went untracked by the Celtic defence and from a Xavi cross, his diving header from right in front of goal was tipped up and over by the English keeper.
It looked like it might be Celtic’s night when David Villa hit the post with a low right foot shot from the edge of the penalty box in the 89th minute, only for the referee to signal Barcelona would have another four minutes to find the winner.
It came in the 93rd minute when Emilio Izaguirre and Beram Kayal failed to stop a cross to the back post where Jordi Alba was on hand to slot it home and break Celtic hearts.
I said before the match that avoiding embarrassment was possibly the best that Celtic could hope for.
They came agonisingly close to taking a point but everyone involved can be rightly proud of a superb defensive performance against one of the best club sides ever seen.
Barcelona - Valdes, Adriano, Mascherano, Bartra, Alba, Song, Xavi, Iniesta, Alexis (Villa), Messi, Pedro (Tello)
Celtic - Forster, Lustig, Ambrose, Wilson, Izaguirre, Brown (Commons), Wanyama, Ledley, Mulgrew (Kayal), Samaras (Forrest), Hooper
Player of the match - Andres Iniesta. Fraser Forster, with some superb saves ran him close, but Iniesta was a constant menace. His close control and ability to commit a defender being at the heart of every threatening Barcelona move.
Follow Daniel O'Connell on twitter @DanielOConnel18