Make no bones about it. Barcelona is the better team. They are one of if not THE best team in the world by a long way. However, how do you beat a team like that?
You do it like Chelsea did, with your brains.
Mourinho did it with Inter Milan, even with his Serie A title winning team at Inter he knew he cannot go fist to fist aganist Barcelona. There are very few teams can out play Barcelona (if that is what people mean when you want to beat Barcelona by more than the score line), Arsenal tried it at home and although they won, Barcelona still had most of the possesion.
It is like a boxing match, you play to your strength and weaknesses. Barcelona has 1 tactic, and that tactic involves keeping the ball more than you. It is almost a given that they will have most of the possession, and when you don't have the ball, you Defend.
It is not a hollow victory at all, it was a masterclass in tactics. Arsene Wenger tried it a few times in the last few years with his own flowing football but unless he has better players, he is not going to beat a team like Barcelona that way.