Pep realized that MSN were not going to help out the midfield much, so the long ball and winning the SECOND BALL IN MIDFIELD would help us keep the pressure off us in and around our own box, while helping us have a constructive starting position of 30-50 yds from their goal. There were times when we not only overloaded them in midfield, but we then surged forward with enough players to overload their defence, too.
I think it has been a VERY long time since anyone has had as many realistic goal scoring opportunities against Barca as City had in that second half.