I was talking about deploying Kalou as a purely defensive player, to do nothing but chase and tackle and when he does get the ball, lay it off to a better player or dribble it as far as possible. Mata's a bit too good for that. Mata can start, if, say we get to the 80th minute at 0-0 we could sub him off for Kalou or a defender. If we're 1-0 up, get Mata off at the hour mark to save him up for the Newcastle game because Barcelona most likely won't score 3 in half an hour.