BBC Utd are asking the question, I personally don't think it had that much of an adverse effect on their performance, their 2nd half possession game showed that, maybe the intimidating atmosphere in the ground played it's part early on.
No doubt the answers on the BBC article will say the opposite.
"16:21
*Beep, beep, beep*
Man City v Man Utd (17:30 BST)
Talking of buses...
City arrived at Etihad Stadium with a more subdued welcome earlier today after that barrage of missiles at Anfield on Wednesday evening.
How much of a factor was that in the 3-0 Champions League quarter-final first-leg win for Liverpool?
Have a look a the footage from the bus before the game."