Arsenal won the first leg 2-1 despite Barcelona having much of the play, and are wary of the Catalans after losing 4-1 in Barcelona last year.

Wenger said: "Is it realistic to go there to try to play a 0-0 from the first minute on? First of all it would be considerably against our nature and even tactically I don't think it is defendable. We have not a team with 11 defenders who are happy to defend"