We are able to play in a way that is uncomfortable for barca to play against (and Del Neri would play in such a way 100%), Real did the opposite today. But we would still probably lose.
In what way though? Straight 4-4-2 with little possession?
I don't think we would have faired much better, especially with our fullbacks. But then again, Barca wouldn't have been as pumped for the match, plus they seem a bit more restless against Italian sides.
Overall, there isn't really any basis for saying we would have done better than Mourinho.