Casillas did not start but when Mourinho was talking to him just before he came on, he barely even looked at his manager.
Everything Mourinho does is to win games, so whatever analysis you have of his decision you have got to start with that. Mourinho is seeing a Real Madrid team that is 16 points adrift of Barcelona and is in a situation he has not seen since he was at Porto.
He believes that dropping Casillas is a way to shake things up and to unsettle a side where he has lost the changing room - and it is quite clear that he has lost a huge percentage of them. Those players, led by Casillas, feel that he has not given them enough weapons to win games, while Mourinho feels that they are not following his path.
The decision to drop Casillas is a mixture of sporting decisions to make sure he keeps on working hard to get his place back and to be at his best for the Champions League which has become the only real target for Real Madrid this season, but there is also some politics going on there too.
There will be an interesting continuation of the Mourinho and Casillas clash. Mourinho is happy at the moment; he is happy because he is making the decisions and it does not matter how many people challenge his decisions, he just wants to do things his way. However this is not going to be sorted easily and I don't think Jose Mourinho will be at Real Madrid next season.
As for Barcelona, well I apologise for my rant at half-time on Sky Sports during their win over Espanyol. My team was losing 4-0 and it was just the wrong attitude, the wrong performance and it was just very disappointing.
There are other teams who have challenged Barcelona much more with the same amount of quality throughout the years but we did not manage to do that.
Barcelona are very sharp though and I think the starting XI in that game will be the team that would play in the Champions League final - perhaps Adriano instead of Dani Alves - but the rest will be just as you saw it in the win against Espanyol.
That means that David Villa will be on the bench and although Barcelona are insisting that they don't want to let him go in the January, I don't think that he has got the legs any more.
Guillem answers your questions...
Got a question for Guillem? Then send it to email@example.com or use the feedback form below, and then look out for his answer next week.
Hi Guillem. In your view what is the best option for Barcelona concerning Gerard Deulofeu? I have watched the kid a lot playing for Barca. Are we right to say that getting Neymar would hinder his progress as we already have a lot of players who can play left wing?
GUILLEM REPLIES: Every talent will adapt to any situation. Quite clearly if you have Neymar, Deulofeu and Messi then you have an amazing amount of talent. They will all find their positions though and it will be built around Messi - even Neymar. It is a bit early to see if Deulofeu will make it to that level but he has taken the steps to get there. He just needs to focus on football and take it step by step. Some people have questioned his mentality but he is still a young man.
SHOULD MESSI MOVE?
Do you think Messi needs to try another European league to be classed the best in the world of all time?
GUILLEM REPLIES: Really? Really? Do you question if Messi is not one of the best of all time if not the best? Winning a World Cup may make a difference in the eyes of many people but the consistency of his high level has been superb. I don't think going from league to league will make a difference - he is already in the best team in the world and is making them the best team in the world. Isn't that proof enough?
BUSQUETS FOR UNITED?
Guillem, Any chance Sergio Busquets would come to the Premier League for Manchester United?
Thanks, Barry Lee
GUILLEM REPLIES: There may be talk about his contract in the press but I don't see him leaving Barcelona - I actually see him becoming the next captain of Barcelona.