If it was Barca's team play that ripped the Londoners to shreds in the first hour of last week's first leg, it was the sublime talent of the Argentina international that propelled Pep Guardiola's side to a 6-3 aggregate victory and set up a last-four clash with Inter Milan.
Arsenal grabbed a shock lead through Nicklas Bendtner in the 18th minute but from then on it was all about Messi, the 22-year-old scoring goals of sheer class in the 21st, 37th and 42nd minutes to all but kill off the visitors' hopes.
NEWS:Messi leaves Arsenal trailing in his wake
With two minutes of normal time remaining, Messi completed his virtuoso display with a fourth after pouncing on a rebound to drill the ball low through the legs of Arsenal goalkeeper Manuel Almunia.
'SPECTACULAR FASHION'
The fourth took his tally in the competition to eight, putting him top of the scoring chart, and added to the FIFA World Player of the Year's 26 La Liga goals this season.
"We started badly but ended in spectacular fashion," a euphoric Messi told Spanish television. "I am very pleased but the important thing is that the team keeps winning."
Barca seized early control of possession at a packed Nou Camp and Messi tested Almunia with a fierce drive in the fourth minute and sent a curling strike whistling just over the crossbar shortly after.
It was a sign of what was to come but the visitors silenced the home fans in the 18th minute with a breakaway goal.
Abou Diaby robbed Gabriel Milito in midfield and as the Barca players appealed for a foul Theo Walcott raced clear on the right and set Dane Bendtner up to score at the second attempt past Victor Valdes.
The goal seemed to fire Barca into action and they were level within three minutes when Messi picked up a loose ball on the edge of the area and lashed a shot through a crowd of defenders into the top corner.
He made no mistake with a cool finish high into the net from close range after Pedro's smart layoff to put Barca ahead on the night and his third goal shortly after was the pick of the four.
Seydou Keita nodded the ball into his path, catching the Arsenal defence flatfooted, and as Almunia advanced to meet him Messi scooped the ball over the Spaniard and into the empty net.
As Arsenal tired, Messi struck again in the 88th minute, twisting one way and another through a crowd of defenders before beating Almunia for a fourth time.
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