1) Oxlade-Chamberlain is continuing to impress
The winger played a pivotal role in Arsenal's first-half dominance, continually causing problems down Manchester United's left side. He created five chances and completed four successful take-ons - more than any other player on the pitch. He appears to be learning from Alexis Sanchez a lot. There were many times throughout the game when he would hustle to win the ball and track back to help in defence, much like his Chilean teammate.
2) Arteta's excellent performance
The game against Manchester United saw the return of captain Mikel Arteta. The midfielder put in an excellent defensive shift, regularly thwarting the attacking threats of Wayne Rooney and Robin van Persie. Despite being thirty-two, he showed an enormous amount of energy throughout.
3) Giroud's return
Another player who made his return was Olivier Giroud. The Frenchman has made a remarkable recovery from a fractured tibia suffered back in August. Although he started the game on the bench, he was subbed on for Aaron Ramsey with fifteen minutes left. He immediately made an impact, providing a different dimension in attack and showing great link-up play with Welbeck. His return was marked with a fantastic finish late on, despite only being a consolation.
4) Arsenal need to learn to take their chances
Arguably, the turning point of the game was Wilshere's missed one-on-one with thirteen minutes gone. From that point onwards, Arsenal fans got the feeling that it just wasn't going to be their day. Despite having twenty-three shots, it took Arsenal until the ninety-fifth minute to score. Their inability to take their chances to kill games off has cost them on numerous occasions so far this season.
5) There is still a complete lack of balance in the squad
Why on earth was Mertesacker in the right-wing position with fifteen minutes to go? Yes it was 1-0 and Arsenal were chasing the game, but his lack of composure and positional sense resulted in Manchester United getting themselves into numerous 2vs1 counter-attacking situations, against makeshift centre-back Monreal. This seems to be a recurring theme this season, with Arsenal finding themselves in similar positions against Anderlecht and Swansea as of late.