United have been excellent. The main improvement from previous games is their passing, which has been exquisite. The four of Rooney, Nani, Ronaldo and Berbatov are causing all sorts of problems, and the fact they are so interchangeable is making it even harder for Celtic to track them. Darren Fletcher needs to get in the game more and Anderson has worked hard, getting forward well and also tracking back to places like right-back. Evans has dealt with any potential trouble well, and John O'Shea is putting in a decent shift at left-back.
The signs are good for the second half, the Fletcher miss before half-time would've deflated Celtic completely, but as it goes they are still in this so we need to find the killer goal in the second half.