Chelsea stun Barcelona in Champions League semifinal

(CNN) -- Chelsea stunned titleholders Barcelona with a 1-0 victory in the first leg of their European Champions League semifinal on Wednesday

Ivory Coast international Didier Drogba scored the only goal of the game late in first-half injury time at a rain-swept Stamford Bridge in west London thanks to a rare mistake by Barcelona's Lionel Messi.

After watching Spanish league leaders Real Madrid lose to Bayern Munich the night before, Barcelona had hoped to avoid any slip-ups as they attempted to defend their title.

And the game appeared to be going their way as they dominated possession with Messi creating chances whenever he got on the ball. But the visitors were profligate in front of goal with Cesc Fabregas particularly guilty, the Spain international missing a hat-trick of clear-cut chances.

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As halftime approached Chelsea grew in confidence having weathered the initial storm and took a shock lead with the very last kick of the opening period.

Messi's rare lapse in concentration allowed Brazilian midfielder Ramires to career down the left wing.

With few options in front of him Ramires fired a low ball across the penalty box which eluded Barcelona's defense before somehow finding Drogba lurking at the back post.

Barcelona goalkeeper Victor Valdes could do little but palm the striker's first-time shot into the back of the net.

Despite Barcelona experiencing the rare feeling of being behind at halftime, it was Chelsea that grew more comfortable as the game progressed, snuffing out the Catalan club's attacks with increasing confidence.

Yet deep in injury time Barcelona could have leveled the tie and score a crucial away goal, but substitute Pedro hit the post with his low curling shot and Sergio Busquets blazed the rebound over the bar.

Chelsea -- controversially knocked out of the competition by a late Barcelona goal in 2009 on the same ground -- held on for a famous victory.

"It was a great result. When you play Barcelona you have to do a lot of defending, just try and limit their threat and be clinical with your chances," Chelsea's interim coach Roberto Di Matteo told British network ITV.

And clinical they were. Drogba's goal turned out to be Chelsea's only shot on target in a game where Barcelona enjoyed the majority of possession: Chelsea completed 194 passes while Barcelona managed 782, almost four times as many.

Yet the one statistic that counts is the score and for those that played in the last Chelsea-Barcelona Champions League semifinal in 2009 -- where Chelsea had five clear penalty claims turned down before an injury-time Andres Iniesta goal clinched their place in the final -- the victory was sweet revenge.

"I think we've learned, we've improved from three years ago. Now we're going to go there, have a go and try to qualify (for the final)," said Drogba.

Now attention turns to the second leg at Barcelona's Nou Camp.

"It's going to be tough there," admitted Drogba. "They will have opportunities. We respect them. But we're not in awe of them."