I thought he was generally excellent, really seemed to read the game well today.
Completely agree, his positioning has improved no end. What I've also noticed over the last few games is that no-one wants to get in a physical battle with him. Zlatan kept drifting away towards Sagna in both games and Costa seems to have learned his lesson too! I think he lacks confidence in his passing, he hits it to where the player is, rather than in front of him, but if he sorts that out he'll be superb.