Barcelona:
In Barcelona's 4-3-3 formation the team clearly plays around Lionel Messi. Messi continues to grab accolades as the top player in the world with timely runs and precision shots. Saying that, United will counter with the Premier League's best defender Nemanja Vidic. Vidic is physical and plays with tremendous pace, but his match up will be difficult as it will consist more of stopping Messi while on the run. Messi is the best at breaking down defenses and if not contained the goals will come plenty.
Barcelona play maker Xavi, is an excellent passer, protects the ball very well, and plays with composure. There is no doubt he's the quarterback creating opportunities for the front line, and also a decent ball winner defensively. But Xavi has had trouble when pressed by high energy defensive midfielders. United could have the advantage if either a fit Darren Fletcher or Park Ji-Sung are used to attack or shadow Xavi, disturbing the flow of play and making it hard for him to pass effectively and set up the front three.
Manchester United:
Sir Alex has a difficult task at hand deciding tactically how to play Barcelona. The 4-4--1-1 with Wayne Rooney playing behind Javier Hernandez has delivered excellent results. With Barcelona's high playing style, this could be an effective way for United to press and create opportunities. Hernandez is quickly emerging as a premier forward and because of the danger he presents, it has allowed Rooney to regain the same form he showed last year.
IF Ferguson decides to pack the midfield and defend deep, it would split up Rooney and Hernandez but could make it hard for Barcelona to get the ball to the front line by making them take possession of the ball deeper. this will help United in taking advantage of a Barcelona team that's weak against the counter.
Throwing the Technical mumbo jumbo out of the window, if United attack, are physical, and do a good job of cutting down passing lanes in the middle, they will win this match. Barcelona will win if they control the game with passing and are patient and timely with runs. They also have to do a good job defensively on counters.
X Factor: Set Pieces
I think the more physical United team has the advantage here. Could ultimately win the game here.