Barcelona claimed their 100th Champions League win courtesy of a stoppage-time winner against a Celtic team who emerged with tremendous credit, if no tangible reward.
The Scottish side had stunned the Camp Nou by taking the lead, the seventh time this season that Barcelona have seen the first goal of a match go against them. Once again, though, they recovered from that setback, Jordi Alba stealing in at the back post to secure a home win.
Celtic still have genuine aspirations of a place in the knock-out stage but this will still prove a wounding loss. Barcelona were victorious and will claim deservedly so on the balance of play but they should also have offered quiet respect.
Celtic are hardly alone in arriving at Camp Nou as massive underdogs but for the Scottish champions that must have been a strange feeling. On the domestic scene this season Celtic will be regarded as the strong favourites for virtually every match they play; the absence of routine Old Firm fixtures for the time being has been offset by Champions League involvement.
Entering this match, Barcelona had won 14 and lost none of their previous 17 home games in this competition.
Spartak's win over Benfica in Moscow in Group G's early kick-off ensured Celtic would finish the evening at least in second place, regardless of events here. An impressive Celtic win in Russia earlier this month triggered the legitimate sense that Neil Lennon's team would essentially be afforded two free hits at Barcelona.
Lennon's counterpart at Barça, Tito Vilanova, was subjected to some pretty fierce interrogation by the local media on Monday evening. The motivation for that was the loss of four goals during Saturday's match at Deportivo La Coruña; Vilanova could and did reasonably point to the fact his own team scored five.
The 21-year-old centre-back Marc Bartra was handed a rare Barcelona start for Celtic's visit. Cesc Fábregas, who excelled in La Coruña, dropped to among the substitutes. Lennon was delighted to be able to call upon his captain, Scott Brown, who is plagued by a hip problem.
Barcelona remain unbeaten in La Liga this season but the concession of 10 goals in their last six outings apparently constitutes cause for concern. If nothing else, that supplies one minor indication of the Catalan team's standards.
There should have been little surprise attached to the fact Celtic spent the opening exchanges toiling to get out of their own half. Alexis Sánchez, preferred in the home attack to David Villa, should have opened the scoring within two minutes but screwed wide from a Lionel Messi pass.
Bartra was the next to threaten, with a header which Fraser Forster batted away. From the subsequent break, however, Celtic created ripples across the European football scene by opening the scoring.
A foul on Brown during the visitors' counter-attack allowed Charlie Mulgrew to curl a menacing free-kick into the Barcelona penalty area. Georgios Samaras was afforded sufficient space to angle a header goalwards; the ball also took a crucial deflection off the shoulder of Javier Mascherano. Víctor Valdés therefore found his first touch of the ball was removing it from his goal net.
Celtic suffered a double blow in the first half's dying throngs. Samaras limped from the field, moments before Andrés Iniesta played a wonderful one-two with Xavi and supplied a low finish. Suddenly, the tenacity shown by Celtic when not in possession had been clinically undone.
Barcelona's vulnerability at crosses was highlighted again, eight minutes after the restart. From a Mulgrew corner, Efe Ambrose headed wide with the Celtic defender's team-mate, Victor Wanyama, actually better positioned. By this juncture, the game was highly entertaining and, to Celtic's immense credit, not nearly as predictable as even some of their own supporters may have feared.
Messi was denied by a fine Forster save – Pedro the supplier – as Celtic endured a subsequent spell on the ropes. Brown had been the first to succumb to fatigue, the midfielder being replaced by Kris Commons shortly after the hour.
Forster, who was part of the England party for recent matches against San Marino and Poland, endorsed that status with a one-handed stop from a Messi header. With a quarter of an hour to play, Celtic were battling to stem a pressure flow.
Just when Lennon's men looked like holding firm, Alba popped up. Adriano's cross eluded the entire Celtic defence, with his fellow full-back scoring from all of two yards range.