Arsenal have destroyed PSV in Philips Stadion, I don't think it's gonna be a hard match against Manchester United. Manchester United not even able to beat Real Sociedad. Arsenal lost several important players, but don't forget Manchester United almost lost half of their players.
Liverpool to not become a champion in this season is like 1% because they have many match against weak teams: Southampton, Everton, Fulham, Leicester City, Tottenham and Crystal Palace.
Arsenal will definitely win this game. When you predict the next fixture to be played between Arsenal and Manchester City, Arsenal has more chances to win than the Manchester United considering the previous fixtures as well as their current performance situation. Currently, Arsenal, despite their inconsistency in the beginning were able to stabilize their performance to win more games than lose. When you now look at the last 5 fixtures, Arsenal have won in all 4 games leaving Manchester United with only a chance to have won them, which happened in the last game they both played.
Arsenal have no chance of winning the Premier League title. This team is not able to perform consistently well. That is why Arsenal has fallen behind. Arsenal's point gap with Liverpool is now 13.
Truth be told, it will be quite difficult for Arsenal to emerge the winning of the Premier League title this season. How I wish they did, but again the reality is that it is difficult to see that happened. Arsenal is already behind the Liverpool guys with 13 points difference, and 6 points ahead of the Nottingham Forest at the moment. Arsenal is already winning against Manchester United which is another additional 3 points for the guys. If that truly works, it means Arsenal will be closing a 3 point gap between them and Liverpool, that doesn't mean they will still win this title.