Despite losing, Arsenal actually played quite well and had several good chances which could have been goals. It's just that Emiliano Martinez played very impressively and managed to thwart several opportunities that Arsenal had. This is certainly a heavy blow for Arsenal, though they dominated the game and had more chances than Aston Villa, but that still doesn't guarantee that they won't lose to their opponents because in football anything can happen.
Aston Villa this season always surprises the big teams, now they have managed to beat teams like Man City, Tottenham, Chelsea, and now Arsenal have been defeated, only Liverpool and Newcastle are unbeaten.
Playing well is useless if they lose, and this defeat is a big loss for Arsenal. How could it not be, when their competitors lose, Arsenal also suffers defeat. In fact, Arsenal should be able to take advantage of this opportunity to be ranked first in the EPL. In my opinion, Arsenal's mentality this season is still doubtful about being able to win the EPL League trophy.