#1 Mourinho's siege mentality
Jose Mourinho is a man who will never settle for what he has. He's always got the hunger to win more and with so much pressure on him, he will only look to thrive. With so much talk about him on the verge of being sacked, Jose has a point to prove and the Manchester Derby will be the best stage for him to show the board and the fans that he is the right man for the job.
A large part of the United fan base is slowly turning its back on the manager but a good performance in the derby will be enough for them to change their minds. The United faithful were happy with the side's effort in the Chelsea game and have been demanding for more of the same.
Even if Mourinho does go defensive, they will have to play the way they did vs Arsenal at the Emirates last season. The Gunners kept attacking but United were solid at the back. Thanks to some stunning saves by De Gea, and the counter-attacking goals, they were able to win the game 3-1.