Actually, it wasn't even the best of 2009, most of the 30 goals wasn't there. In 2010 he has scored even more goals, and most of them are goals that maradona could have scored only once in his life. I think this guy is the best dribbler I've ever seen. When he's high, h'es truly unstoppable. Watch his 2010 goals in youtube to see what he's been doing almost every week.
That said, he can be stopped as any other human, but it requires great teamwork to stop him. In my oppinion, if Arsenal tries to play bravely and attack they have more chances to win than playing conservative. I've seen many many teams in our stadium and the only ones that have taken any profit are teams who try to have the ball and attack. Those who come to defend end up beaten badly (except Rubin Kazan that had the biggest portion of luck I've ever seen in 90 minutes).
So, I think if Arsenal can hold possession of the ball, it can inflict a lot of damage to us. And precisely Arsenal is one of the few teams that can do this. So, from my point of view, Arsenal was the worst team we could face in this round.
I'll try to go to the Emirates if I find a ticket and a cheap plane. Those are one of the best matches I could ask for, MY team against my favorite english team!