Luis Suarez struck twice on his return to England as Barcelona taught Manchester City another Champions League lesson with a 2-1 win at the Etihad Stadium.
But after being swept aside by a masterful Barca display in the first half, City at least gave themselves hope for the second leg of the last-16 tie as Sergio Aguero produced a brilliant reply.
City were left hanging on in the latter stages, however, after Gael Clichy was sent off for a second bookable offense and it needed an injury-time penalty save from Joe Hart to prevent further damage.
Lionel Messi had looked like giving the Spanish side a 3-1 lead to take back to the Nou Camp after being felled by Pablo Zabaleta but Hart pushed away his spot-kick and City breathed a sigh of relief.
That they might still be in the tie seemed unlikely at the interval, after Barcelona threatened to produce a performance much improved on the one that saw off City at the same stage last year.
Messi was at the center of controversy after a late night casino visit on Sunday but – until his miss from the spot – it hardly seemed to take the edge off his game.
Without suspended midfield talisman Yaya Toure, City were never able to get a sustained grip on the game early on with Fernando – surprisingly preferred to fellow Brazilian Fernandinho – and James Milner in the central areas.
Milner had an early shot on goal from a free-kick after Aguero was hacked down by Javier Mascherano just outside the area but his low effort was blocked.
That was about as good as it got for City for a while as Barcelona soon moved through the gears.
Martin Demichelis, the villain of last year's first-leg loss, twice rescued City as he blocked a shot from Messi and then headed away a Suarez cross after the striker surprisingly opted not to shoot.
Former Liverpool star Suarez had actually looked rusty in the early minutes with a few touches going astray, but he soon put that right in emphatic fashion after 16 minutes.
The Uruguayan's luck changed when he got his head to a Messi cross and the ball rebounded kindly to him off Vincent Kompany. The angle was tight but he made no mistake with a lethal low strike.
Dzeko, one of City's livelier players, headed a chance wide for the hosts but it was a rare opening.