#4 Arsenal's profligacy and the lack of defending
Arsenal recorded 33 shots in the game against Manchester United. 14 out of these were saved by David de Gea, some were off target and one was converted into a goal.
However, the scoreline could have read a lot different, if only Arsenal had been a little more clinical in front of goal.
Alexander Lacazette - who started the game despite Wenger ruling him out for the game due to a groin injury - enjoyed one of the best games of his relatively short Arsenal career, but failed to convert it into goals to win the game for his side.
Mesut Ozil - the subject of immense criticism in recent times, and one who has been linked with a move to Manchester United - had one of the games of his Arsenal career as he created chance after chance for his teammates, who failed to bury them.
Manchester United, who were second best for most parts of the game, scored through two defensive lapses by Arsenal in the first half. First, it was Laurent Koscielny, who allowed Antonio Valencia to bomb into the box and finish off the opener.
Then, it was Shkodran Mustafi, who gifted the ball away near his penalty box only to see his side concede a second, despite having been the better side.
The third goal can also be attributed to some poor defending by Koscielny, who failed to hold off Paul Pogba, as the Frenchman set up Jesse Lingard for the third.
Arsenal got everything right in the game apart from the 3 defensive lapses, which turned out to be the difference between a win and a loss at the end of the game.