An injury-time goal from Jordi Alba stunned Celtic and gave Barcelona a dramatic 2-1 victory in their pulsating Champions League Group G clash at the Nou Camp.
Celtic had led at the famous stadium when, in the 18th minute, Georgios Samaras' header from a Charlie Mulgrew free-kick went in off the back of Barcelona's makeshift centre-back Javier Mascherano.
But a minute before the break Barcelona midfielder Andres Iniesta levelled, and with the four minutes of injury time almost played at the end of an exhausting evening, defender Alba sneaked in at the back post to slide in an Adriano cross. The Celtic players were applauded off by their fans and manager Neil Lennon would surely have been proud with his side's spirited performance.
Moreover, with Spartak Moscow beating Benfica 2-1 at home, the Hoops remain in second place with four points from three games as they await the visit of Barcelona to Glasgow for the return game in a fortnight.
Celtic should have gone behind in the second minute when Iniesta split the Hoops defence open with a sublime pass to find Alexis Sanchez but his shot sped past the far post. The home side, as expected, had the vast bulk of possession but were far from purposeful.
It seemed like a matter of time before Barcelona, although more methodical than magical, would get the breakthrough. However, the first half turned on its head within a minute. Fraser Forster pulled off a great save from Marc Bartra's close-range header after the rookie defender had got on the end of an Iniesta cut-back following more prompting by Messi.
The Scottish champions took immediate advantage of their good fortune when Sanchez conceded a free-kick for a foul on Scott Brown wide on the right. Mulgrew's whipped-in free-kick was met by the head of Samaras and the ball came off the challenging Mascherano and went past the helpless Victor Valdes.
Barcelona were stung into action and had many chances to level before Iniesta, after taking a Lionel Messi pass, worked a one-two with skipper Xavi Hernandez before sliding the ball past Forster from 12 yards as he slid to the ground.
Barcelona dominated possession in the second half as the pressure built, but Forster was in outstanding form as he made a series of saves to show just why he had been included in Roy Hodgson's England squad for the World Cup qualifiers against San Marino and Poland.
As Barcelona camped at the edge of the Celtic box, and the defending became more desperate, Forster made further fine saves from Sanchez and Messi. Barcelona substitute David Villa, on for Alexis Sanchez, crashed a drive off the base of the post but just when it looked like Celtic would hold out, Alba popped up with the winner to break Hoops hearts.