I know many believe Barcelona has no weaknesses especially with a number of the worldcup winning Spain side in their team but they do. Tonight Barcelona's defence is without Carles Puyol, their centre half and leader, and Sergio Busquets is likely to be an emergency replacement. Right back Dani Alves likes to go forward, left back Maxwell is a weak link and Eric Abidal is a better full back. There are chances to be had.
2) Mental strength
Arsenal need to stay cool and make sure they don’t intimidated by Barcelona or their 90 thousand plus fans that will attend tonights fixture. They may have destroyed Arsenal last year, but they are not invincible. Just focus on the win at the Emirates and remember they can be beaten. If Arsenal build them up too much because of Lionel Messi's one-man demolition job last year, they will never knock them down.
3) Close them down
Very obvious but last year, with Arsenal's injury-hit defence relying on Mikael Silvestre, Barcelona were given the freedom of the Nou Camp. This time, Jack Wilshere, Abou Diaby and Cesc Fabregas must put in the work rate to close Barca down and stop their midfield architects like Xavi and Andres Iniesta getting into gear.
The Arsenal captain says he is fed up of hearing how he wants to join Barcelona and that he will show his commitment to the Gunners in the Nou Camp. Fabregas has wonderful ability, motivation and desire to play the game of his life tonight and tear Barca apart with one killer ball.
5) Be ruthless
Arsenal boss Arsene Wenger wants Robin van Persie involved because he is worried whether Nicklas Bendtner and Marouane Chamakh will be ruthless enough. Arsenal have some brilliant players, like van Persie, Samir Nasri and Andrey Arshavin, and when chances come - and they will - then they must be taken.