Madrid, Mar 13 (IANS): Leo Messi was the architect of a magnificent display by Barcelona as they overturned their 0-2 first leg defeat to AC Milan registering a 4-0 win over the Italians in the Camp Nou stadium in a Champions League round of 16 second leg match here.

The importance of Barca's achievement here Sunday is made clear by the fact that no side had ever overturned a 0-2 away defeat to AC Milan in the Champions League, reports Xinhua.

Messi scored his side's first two goals to level the tie before halftime, before second half goals from David Villa and Jordi Alba sealed a historic win on a night the entire team showed that rumours of their demise are greatly exaggerated.

The only surprise in the Barca line up was the inclusion of Javier Mascherano who started alongside Gerard Pique instead of the veteran Carles Puyol, while David Villa was preferred in attack ahead of Alexis Sanchez.

The Barca players had promised to correct the errors they committed in the San Siro Stadium three weeks ago and cheered on by a packed Camp Nou Stadium, they went at their rivals from the start with a pace of aggression that has been missing from their game in recent weeks.

Messi needed just five minutes to open the score with a powerful shot into the top corner of the Milan goal, leaving goalkeeper, Christian Abbiati completely helpless.

Abbiati was at his best five minutes later to tip a spectacular Andres Iniesta volley onto the crossbar as Barca kept up the pace, winning every challenge and pinning their rivals back.

Abbiati then tipped a Xavi Hernandez shot wide before Barca began to drop the pace following their explosive strike and M'Baye Niang had a great chance to score the away goal that would have left Barca needing four after Mascherano missed a header, but his shot, with just Valdes to beat bounced off the post.

A minute later Messi levelled the tie with another shot from outside the area that was drilled low past Abbiati's left hand.

That 2-0 lead at the break left the tie finely balanced as a Barca goal would see them through while a goal for Milan would leave Barca needing another two, but if the Barca players felt any nerves they didn't show and Villa scored his side's third after a magnificent Xavi pass just 10 minutes after the break.

That prompted a double change from Milan who put Robinho and Sulley Muntari, who had scored in the first leg, into the game, but it produced little change in the dynamic of the match as Barca continued to control the game and play with a verve and pace that had been missing of late.

Alexis replaced Villa and Puyol came on for Mascherano and with seven minutes remaining Adriano Correia replaced Pedro, just after Jordi Alba did well to block Robinho who almost got on the end of a cross from former Barca striker, Bojan Krkic, who had come into the game with 15 minutes remaining.

Only in the last five minutes, perhaps through tiredness or perhaps through nerves, Barca began to sit back, but the threat was more perceived that real and a break in injury time allowed Jordi Alba to net the fourth goal, which meant that with a minute remaining the Barca fans could relax and enjoy a truly historic win.