A goal in each half by Samuel Eto'o and Lionel Messi handed Josep Guardiola's team a sensational treble and dethroned United as continental champions.
Guardiola became the youngest ever coach to win a European treble, following the Primera Liga and Copa del Rey triumphs.
The 38-year-old has also put his name on the elite list of men who have won the trophy on the pitch and then on the dugout.
Eto'o stunner
United welcomed Rio Ferdinand back from injury, whilst Thierry Henry boosted Barca's frontline after recovering from a knee problem.
The opening few minutes witnessed a rampant start from United, with Cristiano Ronaldo getting close on three occasions.
After just two minutes, Victor Valdes had to parry a trade-mark freekick from the Portuguese wizard, who saw a couple of goal attempts going narrowly wide shortly after.
Against the run of play, Andres Iniesta superbly darted his way towards the United area before finding Eto'o, who stunned the holders in style.
The Cameroonian managed a rare feint past Nemanja Vidic to cut inside with ease, before firing in between the legs of Edwin van der Sar. A quite similar goal to the one he scored in the 2006 final versus Arsenal.
From that point, it was one-way traffic for Barca, who dismantled the Premiership champions with their slick passing and incredible skills.
There were no real chances at both ends before the break, but the one-goal cushion wasn’t too disappointing as far as the Red Devils were concerned.
Messi killer
Sir Alex Ferguson brought on frontman Carlos Tevez for defensive midfielder Anderson in an attempt to provide lone striker Ronaldo with some support.
But the tactical move came to no effect against an irrepressible Barca side.
Three minutes after the interval, Henry waltzed around Ferdinand leaving the England defender on his backside, but the Frenchman couldn’t beat Van der Sar, who denied him from point-blank range.
Five minutes later, Xavi saw his freekick rattling off the left-post of Van der Sar.
United were desperate to take the sting out of their mighty opposition's momentum, but Gerard Pique and Yaya Toure had an excellent night at the back to make sure Ronaldo and Co. remain quiet.
Dimitar Berbatov replaced the poor Park Ji-Sung in the 66th minute as Ferguson seemed to be applying a gung-ho stragtegy.
However, Messi put the game to bed four minutes later when he made an extraordinary jump to head in Xavi's inch-perfect cross with deftness.
The Catalans maintained their superiority until the final minute to clinch a well-earned title and complete a hat-trick of silverware this term.
Eto'o's goal
Messi's goal