Alexis Sanchez hit the bar early on and Cesc Fabregas had a weak effort cleared off the line for the reigning champions before Drogba delighted the Stamford Bridge crowd by finishing a smart break in first-half stoppage time.

Chelsea then shut Barca down effectively in a second half where chances were scarce, until Pedro hit the post and Sergio Busquets blasted the rebound feebly over at the death.

As expected, Barca immediately began dominating possession.

An Andres Iniesta through-ball that bypassed the Chelsea defence found Sanchez free in the area, and he deftly dinked it over Petr Cech but unluckily saw his effort come back off the crossbar.

Barca were not producing their best but should have been in front after 16 minutes.

Messi dragged two defenders out of the way before cutting back to Iniesta, whose shot was parried by Cech. The rebound came to Fabregas but he fired wide.

Midway through the half and Barca were slowly turning up the pressure.

First, Fabregas forced a near-post save from Cech before Messi leapt on the edge of the box to head an Alexis cross into the stretching keeper's arms.

A patchy period followed with a few niggling fouls and no great creation, with Chelsea quashing much of Barca's attacking prospects.

Their resistance was nearly broken on 42 minutes, however, when the visitors broke through Messi.

The Argentine slid in Fabregas to his left, but his colleague's attempt to lift it gently over Cech was underpowered and Ashley Cole arrived to clear off the line.

Half-time parity seemed inevitable but, in added time, Chelsea suddenly struck.

Ramires controlled well on the left flank and slipped a perfectly-weighted pass across the box, where Drogba was waiting to finish just past the grasping Victor Valdes, sending the crowd into a frenzy.

Barcelona probed after the break, Adriano cutting in on his right foot to send Cech flying to his left to save, but Chelsea's first corner moments later from Lampard was just missed by a couple of his team-mates.

Sanchez came close again when Fabregas' inventive scoop played the Chilean in at point-blank range, but he had little space to aim into and poked the ball wide.

Messi attempted more than one run forward from deep into the box but was thwarted first by Gary Cahill and then John Terry, with Pedro introduced by Pep Guardiola in place of Sanchez in the hope of better testing the resilient Blues.

It had little effect, though, with clear-cut chances absent and the visitors, short of ideas, looking unlikely to force their way through.

As they pushed up in desperation, Drogba was able to battle past on the break, but his through-ball into the path of substitute Salomon Kalou on 80 minutes was a touch too strong and the opportunity was lost.

Barca came close when Messi's 87th-minute free kick was flicked on by a crouching Puyol. Substitute Thiago Alcantara flashed at it but could not make contact, yet Cech still had to do well to dive and parry.

The visitors, though, should have equalised at the very last.

Despite Terry's excellent initial tackle to snuff out one chance, Pedro sliced a shot against the post before  Busquets, with the goal at his mercy, lofted the ball high over the bar, meaning his side head into next week's second leg one down and without an away goal to their credit.