Arteta has really changed the thinking of the Gunners this season after going head to head against PSG with a win (2-0) they didn't use the champions league game as an excuse of not performing well in today's game against Southampton. A team that caused Arsenal the chance of winning the league title 2 seasons ago, at least they started it by playing out a draw which started Arsenal's down fall.
But today's game was a little bit off color for Arsenal in the first half, where they played like a team that doesn't want all 3pt. In the second half Arsenal fired up and started pressing till they dominated the midfield of the visitors and made the defense to be open to penetrate.
Between Arsenal and City the team that's dropping their style of play at this very stage of the season, I'll say City are slowly dropping that force of dominating every single game in the EPL, they got lucky if not the game would have ended in a draw. I think things are some how not going well for City in that midfield, they need a replacement as soon as possible.