Well, I don't think that matters much. Whether they are playing at the Etihad Stadium doesn't really matter, especially considering the last match Arsenal had with Manchester City at City's home, which resulted in a two against five defeat that Arsenal inflicted upon Manchester City. So even though they were playing at City's home, Arsenal was able to beat them in their last fixture togetherr, as a competition.
I did not see Arsenal successfully defeated Man City with that score and maybe you were wrong to see. The last time the two met in the English League Arsenal won the match with 1-0 at their own home and at the Community Shield Cup they drew. This season both of them only met twice so that Man City was still enough to be favored to win the match. Of course the match will change where the two coaches will study the strategies with each other, both Arsenal and Man City need a victory in the match because they will open the way to win the league.
In all cases Man City is far more favored to come out as champions, because they are far more potential to win matches at home, Arteta has the opportunity to hold Pep Guardiola's draw but the opportunity is still quite small. Now the condition of Man City players is almost fully fit so that their strength will be much stronger, different like matches that take place at home to Arsenal because Man City is not strengthened by creative midfielders like De Bruyne.