#2 Mourinho's Savvy
This man gets a lot of flak. Some United players aren't completely behind what their manager demands from them (we all know who we're talking about) and the manager has been complaining for quite a while now about 1) The players he wants/wanted to sign and the ones he got, and 2) The lack of character and mentality in the current crop.
He is right if you look at it closely. United's biggest stars have been in tatters this season; Alexis Sanchez, Romelu Lukaku and Paul Pogba all putting in poor shift after another. The manager can't be expected to be responsible for the players' shortcomings on the pitch, as it was Pogba who lost the ball 14 times against Southampton, not Mourinho.
Jose started a side with seven changes from his last fixture, as Eric Bailly, Matteo Darmian, Marcos Rojo all started after a prolonged absence. Other than Rojo, almost all fresh faces put in brilliant shifts tonight, much to the manager's and fans' delight.
Darmian covered ground all night not allowing Arsenal so much freedom on the right, while youngster Diogo Dalot also looked impressive in his first league start for United. This is a genuinely good Arsenal side, one with resilience and grit more now than ever, and United must feel fortunate to take a point from them, considering their own form and fortunes.
Mourinho's game plan was crucial for tonight's result, and the manager needs to be backed by the fans as well as the board if the club is to find any success soon.