Things like this are very common in football and considering that both of them are at the same level, I don't think Arsenal's mentality will waver in the slightest. It's just that Arsenal's winning record at home to Manchester City is not as great as expected and they always experience difficulties when they are the visiting team. But it's still a big game and Arsenal will have to give everything to beat one of their rivals.
Arsenal problem is lack of composure when playing with big clubs such as Man city. Arsenal is doing well quite alright but due to their inability to maintain calmness in big matches, I would favor Manchester city ahead of them. It's a clash of boss and his boy and we will see who triumph. The first leg performance can not be used as the basis of judgment because the league is now more tense than ever. Perhaps, Liverpool might be favored if they play draw.
Mental becomes a difficult situation but now especially in this season Arsenal have actually tried to implement a good thing I think where Arteta continues to develop and patch the leaks that exist at Arsenal because it is quite natural when the mentality is still quite lacking especially at this time the age of Arsenal players is still very young so they need to continue to develop their champion mentality so that last season's performance is not repeated.
Currently the season is getting fiercer from the competition for trophies and as much as possible Arsenal must be able to make a better breakthrough especially in the rest of the season this time because when looking at what they always do in each season sometimes one mistake will actually make their situation continue to worsen and it happened again last season. Now they still have momentum and as much as possible for now they must try to make their situation not the same as previous seasons.