Rakitic is a must against City. My only concern is that he woudn't keep up wit Real Madrid's midfield considering their high technicity this season.
If Mascherano doesn't put on a great performance against City, I would play with the following Midfield against Real :
------------------------------Rakitic---------------------------------------
--------------Xavi------------------------------Iniesta--------------------
Alves and Alba's positioning will be crucial if we play with this midfield against Real. The Xavi---Iniesta pair is not what it was in 2012 for instance, BUT with the right adjustments they can deliver extraordinar performances. Let's not forget that Rayo Vallecano put on a huge pressure against us and Xavi--Iniesta did great.
Of course Rayo is not Real but do you really believe that if they put us under pressure Xavi--Iniesta would have big issues ? I don't think so. Xavi, Iniesta and Messi are the best players in the world when it comes to foiling adverse pressure.
My only concern against Real would be their counter attacks. That's why we should have a totally balanced and symetrical attacking system. Imagine Xavi has the ball 40 meters from Real Madrid's goal, that's how I could well figure out how we can avoid their counter-attacks :
--------------------------------------------------Alba--------------
------------Alves-----------------Rakitic--------------------------
--------------------------------------------Iniesta------------------
---------Xavi(b)-------------------------------Neymar------------
-----Messi---------Suarez------------------------------------------
No way will Real have great counter opportunities if we widen their midfield. This is all about keeping the ball and methodically breaking them down. Against teams such as Real and Bayern, having at least 65% of ball possession is a must in my humble opinion.
Anyway this is off-topic at the moment. Let's see what Enrique has in his mind.