Chelsea are on course for the Champions League final – despite conceding two first-half goals and having skipper John Terry sent off at the Nou Camp.
Ramires scored their potentially crucial goal – shortly after receiving a yellow card that means he will be suspended for the final in Munich if his team get there.
Goals from Sergio Busquets and Andres Iniesta put Barcelona in the driving seat, but Ramires’ strike on the stroke of half-time means that as things stand Chelsea will go through courtesy of their away goal.
Leading 1-0 from the first leg, the Blues were dealt an early blow when defender Gary Cahill – outstanding against Barca at Stamford Bridge last week – limped off after being hurt while tackling Xavi.
But up until the opening goal, Chelsea were comfortably soaking up pressure and had restricted their opponents to only one shot on target.
Barca talisman Lionel Messi fired wide of the near post and then forced a good save from Blues keeper Petr Cech after latching on to a flick from Cesc Fabregas.
At the other end, Didier Drogba, who recovered from a knee problem in time to play, occupied the home defence whenever possible and shot wide following a long kick forward by Cech.
Then it all started to go horribly wrong for Chelsea.
Busquets levelled on aggregate, finishing coolly after being played in by Issac Cuenca, and less than two minutes later Terry was red-carded after kneeing Alex Sanchez in the back during an off-the-ball exchange.
Barca took advantage, with Messi setting up Iniesta, who steered his shot beyond Cech to put the Catalan giants ahead.
Incredibly, however, Chelsea hit back in first-half injury time with a beautiful goal.
Ramires ran on to Frank Lampard’s pass before superbly lifting the ball over keeper Victor Valdes.