Luis Suarez’s slick double has given Barcelona a firm advantage over Manchester City despite Sergio Aguero keeping the Champions League tie alive.
Suarez struck twice inside the opening 30 minutes at the Etihad Stadium, lashing an instinctive opener past Joe Hart.
Aguero pulled one back late to keep City in the hunt ahead of their return trip to the Nou Camp, while Juventus enjoyed their own 2-1 win over Borussia Dortmund.
Carlos Tevez and Alvaro Morata scored either side of a strike from Marco Reus, who pounced on a comical slip from Giorgio Chiellini.
Dortmund have finally found form after a horror season to date, but have plenty of work to do to reach the Quarter Finals.