Their four goals were scored by diminutive Argentina star Lionel Messi as he put on another world-class performance, once again highlighting why he is world's best player at present.
He hit a superlative first-half hat-trick after Arsenal took a shock lead through an 18th minute effort from Nicklas Bendtner.
Theo Walcott evaded the offside trap and tamely squared to the Denmark striker in the penalty area.
Bendtner salvaged the poor ball and, as his first effort was saved by Victor Valdes, the big front man reacted quickest to slot home and hand Arsenal a vital lead.
But Messi was soon to take control and he equalised just three minutes later, smashing home from the edge of the area as the Gunners defence failed to clear.
He grabbed his second on 37 minutes, picking up a loose ball before calmly finishing beyond Manuel Almunia and he raised the roof when Pedro played him in one-on-one with the Gunners' stopper.
As Almunia charged out, Messi audaciously scooped the ball over his head to seal a memorable opening 45 minute performance.
Arsene Wenger's side looked shell-shocked but it was no disgrace going 3-1 down at the interval to a side with talent such as Pedro, Sergio Busquets, Krkic Bojan and Xavi pulling the strings alongside the mercurial Messi.
Barca's domination spilled into the second period as they combined flair, panache and aggression in equal doses as Arsenal provided no answers to their sterling attacking threats.
Bojan went close, Messi almost broke clear as he sought his fourth, Pedro looked more threatening as he advanced further up the pitch and Dani Alves' marauding runs caused left-back Gael Clichy a number of problems.
Wenger brought Emmanuel Eboue and Eduardo into the action as they tried to get back into the contest but, with time running out, it was Messi who hammered the final nail in the coffin.
He broke free inside the area before forcing Almunia into a diving save.
As Messi controlled the loose ball, he shifted to the left, throwing Thomas Vermaelen off balance before smashing through the unfortunate Almunia to add gloss to a fantastic Barca performance.
Referee Wolfgang Stark ended the contest, putting Arsenal out of their misery as Barca showed why they are the side to beat once again this season.
They will take on Jose Mourinho's Internazionale in the last-four as they look to retain the crown they won last term.
The Italians grabbed a 1-0 win at CSKA Moscow earlier in the evening thanks to a Wesley Sneijder strike, securing a 2-0 aggregate success following a 1-0 win at San Siro last week.