I'm more than confident that a win over Arsenal alone won't get the team back on track, or as many believe - they can fight for any top again. Yes, beating a team like that is a morale booster, but it's not enough and Chelsea still have too much work to do, I think top 5 is even close to happening this season
I think this is the right momentum for Arsenal to be able to compete again for the title, Indeed the victory against Manchester City was only one match but this had a big impact on the mentality of the players so that they could be even more enthusiastic about the match.
On the other hand, facing Chelsea at this time will be another challenge even though there are still many who doubt Chelsea now but with their successive wins and the new formation with 3 strikers it makes them a little different and quite worthy of being wary of later.
Sterling's movement on the wing is quite troublesome and it is Arteta's job to find ways to reduce this player so that he is not as comfortable on the field.