Unless United can do a Chelsea, and they've proven too often that they can't cope witha marauding team, then SAF has to play to their strength, which isn't defending the penalty area.
Blaming Nani for Evra's defensive lapses - yes he didn't help out a great deal but Evra has been like this all year no matter who has played on that wing. Defensively he a nightmare - another reason why United have to take the attacking approach.
Of course the midfield is the key - it has been in every game. United cannot play a 2 man midfield against City and if Jones is to be brought in it should be as a midfield runner - they will need someone to harass the City midfield; and please not Park who will just fall over all the game.
Giggs should not be played and kept until the last 20 minutes in case he can be used then, if needed.
Unless there is some energy I see United midfield being over run and consequently so will the defense. I think SAF has to take the bull by the horns and really go for a win - playing a holding game will play into City's hands, they will be too quick for United around the box and with Aguero coming back to goal scoring coupled with Tevez I see United defense struggling.