He played bad today. Lost so many balls, plenty of bad passes, or lack of passes. Did not close down enough. Oh yea, and then he scored 2 goals.
His first goal was typically brilliant in execution. The second, of course, was a knock-in that belonged to whichever player happened to be on the end of Alves cutback.
But once again, he's been really lazy off the ball. I wonder if he's still sick? I don't mean for him to be running his ass off like Pedro, but he walked 90% of the time in the final third. Just a little jog, or Xavi shuffle-step to get into position, and he'd be creating a lot more passing options for his team. It's also why he lost some balls, didn't really position himself away from defenders to receive passes safely. He's the main reason Barça looked lethargic today, a big gap in their fluidity.
Bionicman may be right, he needs a rest. Bring him on at the end of the game so he has an opportunity to score a goal or two.