It was the stuff of dreams if you were a Chelsea supporter, or even a supporter of the beautiful game.
Barcelona, the self-styled "greatest club side on the planet" were taught a football lesson at Barcelona's own Camp Nou stadium by the unfancied Londoners , whose display has surely to be ranked amongst the greatest of any Champions' League nights ever.
It could have been so different after Barca scored the first goal and then John Terry, the Chelsea captain, got deservedly sent off in the first half of the game.
A second goal from Barca quickly followed, courtesy of Andres Iniesta, and Chelsea, who had brought in a 1-0 lead from the first leg, stared down the abyss of elimination from the competition.
They were at this stage playing with only 10 men. How would they fare?
And yet, a stunning lob from Ramires of Chelsea on the stroke of half-time brought the sides level on aggregate, with Chelsea, at this stage, going through on away goals. Half-time score: Barca 2, Chelsea 1 (2-2 on aggregate). What next?
What followed was a masterclass in football.
Sure enough, Fabregas of Barcelona earned a dubious penalty for the home team. Messi, the undisputed best player on the planet, who had nevertheless never scored against Chelsea, stepped up to take the spot kick - and promptly smashed it against the crossbar.
As Chelsea continued to defend, and Barcelona ran out of ideas, the interim Chelsea manager made a vital switch. Off went Drogba, the Chelsea striker; on came Fernando Torres in his place. It was to prove a tactical masterstroke.
With 2 minutes to go, and the tie poised at 2-2 on aggregate, the ball broke to Ivanovic of Chelsea in the Chelsea area. A boot up the field and the ball falls to the unmarked Torres, who runs the length of the Barcelona half to round the Barcelona keeper and slot home into the empty net, giving Chelsea the aggregate lead of 3-2.
Pandemonium. In the Chelsea section of the ground, that is; silence in the Barcelona stadium otherwise.
As the final whistle soon blew, it was clear that this was Chelsea's greatest European night ever; and boy did they deserve the result. Well done Chelsea, and KTBFFH (Keep The Blue Flag Flying High).