united can beat them, unless fergie will play the barca type of football which is not something united can overplay tjhem with. we saw it in2009.
if they stay by their style of football, fast wingplays, with nani, valencia crossing to rooney and chico, i think they can beat their defense as it doesn't seem to be too solid.
quesiton is, if united can defence their midfiled, which is in my opinion something what will decide the match, indeed together with defending villa and messi.
but still, i will make some solid bet on united's win.