Celtic were denied a famous point at the Camp Nou as Jordi Alba scored in the fourth minute of stoppage time to give Barcelona a 2-1 win in their Champions League Group G clash.
The travelling supporters were sent into delirium as they opened the scoring in the 18th minute after a sublime delivery from Charlie Mulgrew was headed in by Georgios Samaras, but Andres Iniesta restored parity with a coolly taken goal on the stroke of half-time.
Neil Lennon’s side withstood a relentless barrage of pressure from the hosts with goalkeeper Fraser Forster forced into making a string of inspired saves, and looked set to take away an unexpected point from the Catalan capital, only for Alba’s last-gasp winner to deal a cruel late blow.
The three points saw Tito Vilanova's side maintain their 100 per cent record in Group G with their third successive victory, while Celtic remain second, one point above Spartak Moscow, who beat Benfica 2-1 earlier in the evening.
Skipper Scott Brown, Samaras, Mikael Lustig and Emilio Izaguirre returned to the Celtic side at the Camp Nou, while Vilanova handed 21-year-old Marc Bartra his first game of the season alongside midfielder Javier Mascherano in central defence.
It was all Barcelona from the outset as the hosts dominated the play, and Alexis Sanchez should have given his side the lead in just the second minute as he latched on to a through ball from Iniesta, but slid his shot wide of the far post with just Forster to beat.
The match pitted the side with the best passing accuracy in the opposition half, Barcelona, against the side with the lowest in Celtic, and the point was reiterated as the hosts monopolised the possession, but they could not convert their pressure.
Xavi picked out Messi on the edge of the penalty area with a raking delivery, before the forward chipped an exquisite through ball to Bartra, whose volley was parried away by Forster, and the hosts would pay for their profligacy in front of goal.
Celtic stunned the Camp Nou as Mulgrew whipped over a devilish delivery into the box, and Samaras's header deflected off Mascherano and beyond Victor Valdes. Lennon and the travelling supporters celebrated wildly.
Messi went agonisingly close to levelling with a free-kick which scraped the bar, while Bartra should have scored from Iniesta's exquisite delivery with a free header from close range which he directed wide, and it looked as though Celtic would head into the break with their slender lead intact.
But the visitors were handed a blow as Samaras landed heavily on his ankle and had to be replaced by 21-year-old James Forrest, before Barcelona – who have lost just one of their last 20 Champions League games – drew level.
Iniesta produced the inspired piece of skill required on the stroke of half-time as he played a slick one-two with Xavi inside the Celtic box, and he followed it with a clinical finish as Barcelona were able to breathe a sigh of relief and restore parity.
Celtic had failed to score in four of their last five European games against Spanish opponents, but they could have grabbed their second of the night in the 54th minute as Mulgrew drifted another fantastic delivery to the back post and Victor Wanyama met it unmarked, but he could only head wide from close range as a clear-cut opportunity was squandered.
The pressure was incessant from the hosts as Celtic were boxed in and unable to enjoy any real respite, but the scores remained level past the hour mark as Barcelona attempted to force the issue.
Kris Commons replaced the excellent Brown in the 63rd minute, and the substitute’s first touch almost picked out Gary Hooper, who would have been clean through with just Valdes to beat from yet another counter-attack.
Another incisive move from the hosts saw Sanchez combine with Pedro, before Messi glided in to fire a snap shot on target from close range, only for Forster to somehow claw the ball away with an inspired stop.
Celtic held firm in the face of wave after wave of pressure, and two exquisite dinks over the top of the visitors’ back four from Iniesta saw Sanchez then Messi both denied from close range by Forster.
The visitors defended desperately to cling on for a point late on as substitute David Villa struck a post with a fierce shot, but finally Barcelona found a way through in the fourth minute of stoppage time.
Sanchez drifted a deep delivery to the back post, and Alba stole in at the back post to stab the ball beyond a helpless Forster to deal a cruel late blow on the stroke of the full-time whistle with Lennon left dismayed on the touchline.
Barcelona have now won 15 of their last 18 Champions League games at the Camp Nou, but they were almost denied by a valiant performance from Celtic, who were left heartbroken at full-time.
MAN OF THE MATCH
Fraser Forster - Celtic: Any number of Celtic players could have justly been identified as the man-of-the-match, but Forster's string of incredible saves kept his side in the contest until he was finally beaten for a second time in the fourth minute of stoppage time.
BARCELONA: Valdes 6, Adriano 6, Bartra 6, Mascherano 5, Jordi Alba 8, Xavi 7, Song 6, Iniesta 7, Sanchez 6, Messi 7, Pedro 6. Subs: Villa 6, Tello 6.
CELTIC: Forster 9, Lustig 8, Wilson 7, Ambrose 8, Izaguirre 7, Samaras 7, Brown 7, Wanyama 7, Ledley 7, Mulgrew 7, Hooper 7. Subs: Commons 7, Kayal 6, Forrest 7.