I won't deny the fact that they played very well and perform excellently by creating a lot of chances but one thing about all these pre season game is that sometimes it doesn't really have much effect when the league starts because I have seen on so many occasions that a team will perform so well and at the end their performance didn't go well as they did during the pre season games.
Look, pre-season and league are not the same quality and teams do not play with the same attitude. There is no denying that Arsenal have played well. They even play well in the league, but they are very poor at scoring goals. Arsenal now need only one goal machine to perform well in the league. Maybe the impact is not noticeable in pre-season, but when the league starts you will definitely feel the lack of a striker in Arsenal's team. So do not mix pre-season and regular season, the two are different situations and they are just like warm-up matches.