Since Manchester city is having defensive issue that cost them the loss.. Arsonal isn't, so the probability of Manchester United winning that match is extremely slim, not because they are not strong, but because of the club that they are to face, arsonal's performance Theis season is unlike any other, if it's defence that will be the issue of any loss again Manchester United, then that will not have to be an issue for Arsonal, as their defence is one for the best in the world this season..
If we consider the defense, I am actually worried that United's defense will struggle to handle the pressure from Arsenal's midfield and attack. Unless United can match the battle in midfield and their defense can stay focused and play disciplined, the outcome of the match might be hard to predict. But if United loses in midfield and their defense is poor, a defeat for United is inevitable.
Manchester United's defense, midfield, and attack were okay against Manchester City in the Manchester derby, and if Manchester United's defense, midfield, and attack can perform like they did against Manchester City, they will be able to match up with Arsenal and handle the pressure from Arsenal's midfield and attack very well. Manchester United dominated Arsenal in their first game at old trafford this season, and now that Manchester United is playing well, Manchester United can handle Arsenal and even walk away with 3 points at Emirates stadium on sunday.