Arsenal captain Cesc Fabregas says Barcelona will beat Real Madrid on Monday.
Jose Mourinho, who worked for Barcelona under Sir Bobby Robson, returns to the Nou Camp but Fabregas believes the magic of Lionel Messi could be decisive.
He said: "Messi is a phenomenon. He is like a bull, hardly ever injured, he is a physical evolution. He does things no one else can do. He scores goals, makes them... everything.
"Game after game he does all this. He's the best, he seems to be from another planet. When he gets the ball no one ever knows what he is going to do.
"Real are improved from recent seasons, more dangerous that in the past. No one should be surprised at my feelings for Barcelona. My grandfather took me to the Nou Camp and in our house there was always a very special party for Barca-Real. I do not want my wish to be misinterpreted but of course I want them to win and I think they will.
"Mourinho has made Real more difficult to beat. When he was at Chelsea he made them very strong. They were the best years for Chelsea who were so competitive, so strong. They had no rival in the Premier League but no luck in the Champions League."
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