The visitors dominated possession, as they usually do, and had plenty of goalscoring chances but it was Didier Drogba's goal late in the first half which gives the Blues a slight advantage going into the return leg at the Nou Camp next Tuesday.
Against the run of play, Chelsea managed to nick a goal in stoppage time of the first half when Frank Lampard won the ball from Lionel Messi in midfield before playing a lovely pass onto the chest of Ramires. The Brazilian advanced into the area before cutting a clever left-footed pass into the path of Drogba who finished with enough power to get it past Victor Valdes.
Earlier in the first half, Barcelona were desperately unlucky when Alexis Sanchez was denied by the crossbar when he dinked an advancing Petr Cech from Andres Iniesta's neat ball before the Blues keeper made a vital save to thwart Iniesta with Cesc Fabregas making a meal of the rebound from pointblank range.
Just before the half-hour mark, Cech safely held Messi's powerful header before Fabregas' chipped effort from Messi's through ball was cleared off the line by Ashley Cole who had tracked back well.
The goal on the stroke of half-time stunned the visitors but they continued to create scoring opportunities in the second term and probably should have leveled when Fabregas played in Sanchez who was unable to get a shot on target, as Cole again got back, but the Chilean was a bit slow with his chance.
The 87th minute saw Cech come up with a huge save to deny Carles Puyol's glancing header from a Messi free-kick, diving full stretch to his right, before another big miss from Barcelona occurred when Pedro hit the upright with his attempt from the left side of the area and thn Sergio Busquets getting the rebound horribly wrong in injury time.
But Roberto Di Matteo's Chelsea needed just the one shot on target to eventually win the contest, with Pep Guardiola's charges putting in a subpar performance, but nothing can be taken away from the Blues who have given themselves a decent chance of sneaking through to the final although the Nou Camp will provide a much sterner test.
UEFA Champions League
Stamford Bridge, London - 37,000
Yellow cards:CHE - Ramires 69', Didier Drogba 86' BAR - Pedro 71', Sergio Busquets 76'