Look its the classic sit back, defend deep, hit them on the break tactic. Fergie employed it against us every game, Rooney scored how many times against us. I remember him saying, everyone knows how Arsenal will play so Man U let us dominate possession knowing that defensively we were naive and that they would get opportunities to hit us on the counter. Worked 9 times out of 10 for them and Chelsea over a 5 or 6 year period when we couldn't buy a win against the f***ers.
Its not a new tactic. Difference is Man U under Mourinho play it against top and mid level teams. I think he sets up to not lose rather than to win, hence why I call him a defensive manager.