This year Real Madrid are closer in ability to Barcelona, but Barca have a slight superiority in their collective way of playing which can make the difference. Real need more time to end their rivals' run of success.
And the match tonight is in Barcelona, which will be important.
However the matches are like a knockout tie between the teams: Barca v Real and Real v Barca will define the champions of Spain. The matches have the look of finals.
I expect a tactical battle similar to last year's Champions League encounter between Mourinho's Internazionale and Barca.
Obviously Mourinho is going to defend and counter-attack at the Camp Nou. He has plenty of possibilities for counter-attacking with Cristiano Ronaldo, Mesut Ozil, Gonzalo Higuain, Angel Di Maria and Karim Benzema.
However they will have to support the defence while under great pressure. And Barca have Lionel Messi, who is not only an alien but also an inhabitant of another planet!
Barca have everything that a coach dreams of: a great collective and the genius player who can make the difference when things are going badly.
I like both Messi and Ronaldo, and possess a lot of respect for them. I think that Messi has a slight advantage because he knows how to play individually and within the collective when they need him to.
Ronaldo is more physical than Messi, which can often make the difference, but Messi begins supersonic moves with his team-mates - and, when you know how hard it is to do that in football, you can have nothing but admiration for it.
The Golden Ball is coming up and for me it is between Xavi, Ronaldo and Messi for the award.
I don't especially want to see either side win the Clasico: I'll just watch the match like any football lover. It gives me great enjoyment to watch this match, which does not happen often because of all the matches we are able to watch these days. I would like the team which plays the best to win it.
Unfortunately the aspects that make this such a massive game also mean that La Liga these days is a bit decimated.
In the past it had 10 good teams, whereas nowadays there is only Real and Barca - then the rest. Due to financial parameters the gap is deeper than ever before.