Fergie should have gone 4-5-1, but I believe he was looking to catch us off-guard, and it wasn't looking too bad in the first 10-15 minutes as his team hit the ground running. A goal then would've changed the course of the whole game. However I think that 4-5-1 would've been the better option. First of all Chicharito is a poacher, he doesn't create his chances but finishes the chances created by his teammates. That is why he would naturally struggle if his team doesn't have the ball and are not creating chances, Rooney on the other hand creates chances out of nothing. There was no doubt in my mind that Javier was going to be isolated this game as Barcelona were never gonna let United get much of the ball. The formation I would have gone with would've been:
---------------VDS----------------
Fabio/Rafael - Rio - Vidic - Evra
---------------Fletcher------------
------Carrick--------Giggs--------
Valencia--------------------Na----
--------------Rooney----------ni
Anderson in for Fletcher if the latter wasn't fully fit.
Fletcher would play the Pepe part but with more discipline. Messi was allowed too much space in his second goal, and mainly whenever he beat his first man, had an easy time gliding up into the D. If Fletcher was there to mark him he wouldn't have taken over the way he did. Fletcher has proved he is excellent at playing that role, like in the Arsenal CL semi 2 years ago. The three man midfield will also give Giggs more room to breathe and pick out passes. Giggs was too busy being caught between the Barca midfield passing bonanza as United's midfield was clearly out numbered. If you noticed during the game the numerical advantage Barca had forced Park to frequently operate as a 3rd central midfielder, especially when Messi dropped back, this left Alves with acres of space on the right.
Since I would choose a 3 man midfield, I'd rather have Nani in the flank than Park. First of all his pace will ensure that Alves would have to think twice before wondering too much forward. Second of all he can also operate as a second striker with Rooney, and his pace can trouble Barcelona. Not starting Nani was a mistake and left Alves with too much freedom IMO as Park was too busy covering for United's lacking midfield.
Just my 2 cents...