5-4-1 is known as one of the worst formations, even defending trainers agree to that. The advantage of this formation is that the midfield rating is acceptable, but the big downside is that one wing attack is neglected and central attack also won't be very strong. Scoring will be very difficult with this formation, so it can be used with pressing to make sure you don't lose, or with play creatively and a player with very good set pieces so you at least have a chance to score. CA won't work very well here because only one of your attack ratings is acceptable.
Here is an example of 5-4-1: