arsenal has a target stop in the top 4 is very reasonable IMO. Arsenal's opponent in the EPL match is Brentford and most likely arsenal will win but after that arsenal will face Tottenham and Liverpool, I'm not sure if arsenal will be able to maintain their position in the standings while man city continues to follow from behind with great potential to shift arsenal's position.
Top 4 will always be Arsenal main target for each season because they miss to play at champion league again and their last appearance on this competition was 2016 and since that Arsenal never reach to top 4 again and one thing for sure Arsenal should be consistent because this is one of the biggest issues since Arteta arrived that they seems always have late start compare to other big teams or playing not stable and if this season they can showed their consistency i am sure their target will be achieved and next month will be tight schedules for Arsenal because besides Tottenham and Liverpool they also will fight against Man City
It is very difficult to maintain 4th position in every season because the opponents they face are very tough they must maintain teamwork to maintain their defensive position and when there is an opportunity to attack to score goals, they must be utilized properly and maximally because in the previous match they failed to survive and had to lose to Manchester United, Hopefully in the future Arsenal can still get a win.
Arsenal started the season quite well. This is very different from what happened last season, even Arteta's position was on the brink at the time. Now Arteta has the main task to keep the consistency of his men so that they get a good achievement this season, but I don't think it will be an easy job because every team will definitely be haunted by player injury problems and the possibility of internal problems. If Arsenal can cope with it all, at least they will be able to stay in the top 4.