Errors leave a mountain to climb
Wenger spoke of a “good performance” and “impeccable attitude” from his players but he will be familiar with this feeling.
Only twice in 18 meetings with Mourinho has he got the upper hand and the charitable way in which his side gave away goals will not sit well.
Koscielny’s cross-field pass and Mustafi’s indecision ultimately left a mountain to climb if Arsenal were to record a 12th straight home win in the league.
The ease with which Pogba sauntered into the area to create a third just as Arsenal were seeking to build on Lacazette’s goal also smacked of weakness.
Arsenal can justifiably feel aggrieved by a penalty shout that was turned down late on when Danny Welbeck was caught by Matteo Darmian but by that point, the 10 men of United had finally managed to calm a frantic affair.
Wenger’s side drop out of the Champions League qualification places into fifth. They were superb going forward at times and will scratch their heads as to how they only found the net once but, not for the first time, it was at the other end where their shortcomings showed up.