I know that Manchester City's performance is dramatically declining, and even though Manchester City's injured players are fully fit, there's no guarantee Manchester City previous performance will return. The both Manchester clubs aren't at the best right now, but if Manchester City continues with their current performance when they face Manchester United, I see Manchester United taking all three points from Manchester City this weekend.
Manchester City's problem is that key players have left the team. Currently, they have several different players than before. This is what has caused their decline. Pep needs time to restore their performance, so we must fully support Man City this season and believe in Pep Guardiola that he can fix this problem.
The meeting between the two Manchester teams will certainly be high-tension and interesting to watch. However, Man City will still be favored despite their decline. However, if they face Man United, Man City will try hard to beat them.