F.C. Barcelona Football Formation

Lineup (4-3-3)

As libero Pique can move around without marking a player, and needs to lead the defenders.
Mascherano (being a defender and defensive midfielder) fit the center fullback role.
Alves and Alba play well together, and when they communicate they can both run (in turns) down the field.
Busquets can play well with Mascherano, who does not need to be shaky playing in the last line and they can build up the play well together.
Xavi, Iniesta and Messi play well together and combine well.
The MVP (Messi, Villa, Pedro) combination does wonders.