Keita started well but he's not good enough to be our DM against good sides. Yaya performed against the best last season in protecting our back four so we know he has the ability. Keita has caught the eye with his goals this season but it's been increasing clear of late that he is not good when it comes to assisting Xavi possession wise in the middle. Against Mallorca we had to literally miss out the midfield most of the time (see the first goal) because Keita and Biscuits don't move around looking for the ball and providing an option. Put it this way, when we take on a Chelsea or United, who would you want alongside Xaviesta in the middle giving protection, Yaya or Keita? Obvious choice IMO.