Premier side Chelsea produced the kind of 'perfect' performance Roberto Di Matteo had demanded to inflict Barcelona's first Champions League defeat of the season and give themselves real hope of reaching the final.
The Blues once again proved the nemesis of the team feted by many as the greatest to play the game thanks to an amazing smash-and-grab display in the semi-final first leg at a jubilant Stamford Bridge.
Caretaker manager Roberto Di Matteo's plan paid off spectacularly, Didier Drogba scoring the winner to go some way to burying the demons of the sides' last meeting three years ago.
As well as being magnificent to a man in carrying out the instructions of Di Matteo - whose claim to be appointed manager on a full-time basis is becoming irresistible - Chelsea also enjoyed the kind of luck that deserted them in 2009 and which they have had in spades since the Italian took charge.
They may need plenty more at the Nou Camp on Tuesday to reach their second final after Barca missed a glut of chances after dominating possession from start to finish.
The pattern of the match was set the moment the visitors kicked off, Chelsea allowing them possession to a point and Raul Meireles leading the pressure behind Drogba.
From a defensive point of view, it largely worked, although the visitors should have taken one of the chances to have fallen their way.
Alexis Sanchez hit the bar early on and Cesc Fabregas had a weak effort cleared off the line before Drogba finished a smart break in first-half stoppage time.
Barca were caught upfield and Frank Lampard's ball over the top sent Ramires rampaging forward, the Brazilian's cross picking out Drogba. Victor Valdes should have saved the scuffed finish but could only help it into the net.