For Arsenal to beat Manchester United by 2 goals, that means they might beat Manchester City also if they meet next and with this performance they can go forward in the league.
Arsenal was the better side in the game against Manchester United and the scoreline says it all.
Arsenal may very have a fighting chance when playing against Manchester City but not cause they won Manchester United by 2 goals. Needless to say, Manchester City is not on the same level with Man United and Arsenal comfortably winning Man United shouldn’t be used as a benchmark.
No doubt, Arsenal is in great form and strong enough to perhaps threaten Man City’s chances of winning the title again.