Chelsea's UEFA Champions League hopes are still very much alive following a 2-1 defeat against Barcelona, but the Premiership leaders were left fuming at referee Anders Frisk whose sending off of Didier Drogba turned the game at Camp Nou.

The Blues had survived an early onslaught to edge ahead courtesy of a Juliano Belletti own goal, and looked comfortable as the game approached the hour mark.

However, they were ultimately unable to hold on after Drogba was harshly dismissed following a highly-dubious second booking, succumbing to goals from Maxi Lopez and Samuel Eto'o.

Urged on by a full house, the hosts made a quick start as Chelsea nervously felt their way into the game. On three minutes a misplaced Frank Lampard pass allowed Eto'o to release Ronaldinho, but instead of looking to play the Cameroonian striker back in with Chelsea struggling to cover, the Brazilian chose to shoot and was some way wide.

The same duo were at it again moments later as the visitors' normally rock-solid back-line was made to look more than a little ragged, but once again Petr Cech was not tested as Eto'o blazed wide from 15 yards.

Although Ronaldinho caused a further flutter or two with a delicate dinked effort that went narrowly wide on ten minutes, The Blues settled and began to stifle Barca's attacking threat which looked blunter with each passing minute.

The intricate promptings from midfield of both Ronaldinho and Deco increasingly gave way to speculative efforts from distance with Claude Makelele, Lampard and Tiago snuffing out potential danger in front of their back four with the minimum of fuss at every turn.

Indeed, Deco's attempts to win a penalty with an outrageous dive into the box on the half hour mark suggested that Chelsea's defensive solidity was beginning to frustrate not only the home fans but the home players too.

Having successfully soaked up the early pressure Mourinho's men then produced the classic sucker-punch with their first attempt on the Barcelona goal.

Lampard released Damien Duff - playing after a miraculous recovery from injury - with a lofted ball over the Barcelona defence, and the Irish forward produced a sublime first touch which allowed him to cut in and centre an inviting ball that the retreating Belletti could only steer into his own net with Joe Cole waiting to convert behind him.

As Mourinho's animated celebration on the touchline showed, Chelsea's game-plan had worked even better than the Portuguese tactician himself could have hoped - but it could and should have got better just two minutes later.

Barcelona's high defensive line was once again exposed by a ball over the top with Makelele playing in Drogba, but - with just Victor Valdes to beat - the striker screwed his finish wide of the target from the edge of the box.

The home fans again asked for a penalty on 48 minutes as Eto'o was crowded out by a combination of Gallas and Ricardo Carvalho, but again it was an appeal more in hope than belief as Chelsea set out their stall for more of the same in the second period.

However, their serene progress was rudely interrupted by Frisk on 55 minutes who decided that Drogba merited a second yellow card for contesting what appeared a 50-50 ball with Valdes after Belletti's chest back to the keeper had fallen short.

Barca moved to add more of a physical presence to their numerical advantage by throwing on Lopez on the hour mark, and the powerful Argentine striker almost helped create an equaliser with his first contribution by helping the ball into the path of fellow substitute Andres Iniesta, but the midfielder shot narrowly wide.

However, Lopez himself did restore parity moments later as Barca's barrage of pressure finally told. The hit-man expertly created a shooting opportunity by allowing Eto'o's pass to run across himself, and made no mistake - firing past Cech to register his first goal for the Catalans since his transfer window move from River Plate.

Lopez turned provider six minutes later as Barca forged ahead, although his assist was unintentional. A speculative shot from 25 yards was heading well wide, but Eto'o turned it into the perfect pass as he stole in behind Carvalho to angle it home first time from ten yards.

John Terry produced a typically brave block to deny Deco extending the lead further, and Cech displayed his admirably safe hands time and again in the closing stages as Barca pelted the Czech custodian with numerous efforts from range.

With virtually the last action of the game Eto'o spurned a golden chance by heading wide from Deco's far-post cross, and although there will be frustration in the Chelsea camp at slipping to a defeat, Mourinho will know his side are still well-placed for the return at Stamford Bridge in two weeks' time.