A supreme Barcelona inspired by Lionel Messi swept to a 4-0 victory over Milan to win 4-2 on aggregate and reach the Champions League quarter-finals.
A superb first-half brace from Messi put the Blaugrana 2-0 ahead on the night and levelled the tie 2-2 on aggregate, but just before his second goal Milan striker M'Baye Niang hit the post with a one-on-one which would have left Barca needing four goals to qualify.
The stage was set for a tie-winning Messi hat-trick, but instead it was David Villa who picked out the far corner in the 55th minute following a quite brilliant pass from Xavi.
And rampaging left-back Jordi Alba finished brilliant Barca's job with a close-range strike on the counter deep in injury time.
As expected, Barca attacked relentlessly from kick-off and were rewarded with the key opening goal only five minutes in.
Messi was a shadow of himself in the first leg, touching the ball only once inside the Milan box and failing to get a shot on target. Not so in the Catalan cauldron: when Xavi practically walked the ball to him, he took one touch before bending an unstoppable strike into the top corner from just inside the box.
With Milan wasteful in possession and 90,000 fans clamouring for more, Xavi sent a probing diagonal ball into the box towards Pedro. The Spain winger was somewhat clumsily bundled into by Ignazio Abate, but Hungarian referee Viktor Kassai waved away the protests.
Christian Abbiati was Milan's hero shortly afterwards when Andres Iniesta caught a half-volley beautifully but the diving keeper somehow tipped the ball on to the woodwork and to safety. It was an incredible save at full stretch; he was up quickly as Messi arrived, but the headed rebound from an angle found the side-netting.
Abbiati was then sold short as he emerged from his goal, but Villa - otherwise quiet in the first half - could not find the net with the goal gaping. Xavi then saw a shot tipped wide of the far post.
Eighteen-year-old French striker Niang had only 15 minutes of Champions League action under his belt prior to the match. Yet in that quarter of an hour in the first leg he looked impressive, enough so to convince Massimiliano Allegri that he was worth a start with Giampaolo Pazzini injured and Mario Balotelli cup-tied.
His big moment arrived in the 38th minute, after a period in which Milan more or less stifled Barca's creativity. Javier Mascherano, preferred to Carles Puyol in the centre of defence for his ball-playing skills, misjudged a long ball to put him clean through: he bore down on goal, beat Victor Valdes with a low shot but saw the ball come back off the post.
A minute later Messi had the ball in the net again.
Massimo Ambrosini was caught in possession by Iniesta and he found Messi, who cut in and dispatched ruthlessly inside the near post.
Replays showed that the Argentina star came back from an offside position as he cut inside, but it was a difficult one for the officials to judge.
Had the scores remained 2-2 on aggregate, the match would have gone to extra-time then penalties - but so good were Barca that such a scenario never seemed likely. They ensured that the game would be finished within 90 minutes when Iniesta laid off to Xavi, who pinged a wonderful pass to the right and Villa - and the Spain striker picked out the far corner with a high left-footed finish. Kevin Constant was left floundering as he slid to intercept the Xavi pass.
There were further opportunities to open up Milan, with Dani Alves and Alba especially attacking constantly from full-back, but the Rossoneri - playing higher up the pitch in the second half, with marginally more success - nullified much of the threat.
As time wore on they began to attack in greater numbers themselves. Kevin-Prince Boateng crossed low for Mathieu Flamini to flick for goal from 10 yards out, with Gerard Pique doing brilliantly to block.
Former Barca star Bojan Krkic was thrown into the fray and beat Pique on the left to deliver low into the box, where Robinho's first-time strike was expertly blocked on the edge of the six-yard box by a sliding Alba.
With Jordi Roura - in charge of a turbulent period, by Barcelona standards, with head coach Tito Vilanova holed up in a New York hospital being treated for cancer - looking more than a little worried on the bench, Milan pressed more and more.
And a little too much. Messi had the ball at his feet on the counter but looked content to take his time before finding substitute Alexis Sanchez on the right. He was more direct, sending a low ball to the far post where Alba arrived having flown up the flank to finish under Abbiati and set the Camp Nou celebrating a famous win.
Milan famously beat Barca 4-0 in the 1994 final of this competition - this time that scoreline saw a team overturn a 2-0 first-leg deficit (i.e. without an away goal) for the first time in Champions League history.
MAN OF THE MATCH
Lionel Messi (Barcelona) - The little maestro came alive in the first half to score the brace which sent Barca on their way.
BARCELONA: Valdés 7, Alves 7, Piqué 8, Mascherano 6, Alba 8, Busquets 7, Xavi 8, Iniesta 8, Pedro 6, Villa 7, Messi 9; Subs: Alexis 7, Puyol 6, Adriano 6.
MILAN: Abbiati 8; Abate 8, Zapata 6, Mexes 5, Constant 5; Flamini 6, Ambrosini 5, Montolivo 5; Niang 6, Boateng 6, El Shaarawy 6; Subs: Bojan 6, Robinho 5, Muntari 6.