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
Arsenal are competitive for EPL title this season, we should expect the very best performance from Gunners because everything will work out smooth for them. Afterall they have one of the best competent coach, Mikel Arteta, he's not relenting as he wants the best result for the team. Chelsea have experienced one of their terrible form last season, but this season is different as there would be high level of football from the blues this season. Mauricio Pochettino ensuring the team bounces back to winning levels because everything going to completely play out fine.
It's very possible this season Mikel Arteta wouldn't want that which happened last season to occur again where he was close to getting the league title but ended up finishing in the top five. He Is showing it with how much work he is putting into his team this season and at this point I think the only thing remaining for them would have to be consistency so they can get the trophy by the end of the season.
If they can't be consistent enough to maintain their position it's most likely Manchester city or Liverpool would overtake them and become the champions, another team to look out for is Chelsea as they are gradually picking up form, after their recent series of wins it most possible their morale is pumped high already and they would want to get more wins and build their strength to gain top position on the standing this season, if the eventually get that strong enough then arsenal should be on the lookout as they may have a new contender on the list to challenge.