How to counter this formation???

[John Naish]

I worry about that winger, so if you use 3-5-2 v style you are leaving that flank open. You could use an asymmetrical formation right back at him and make sure you just cover that one flank

True - I'd largely forgotten about that winger - I guess with his two strikers you need 3DC's if you're going 3 at the back, but to cope with the winger you'd want a DL or DML to take care of him, so 4 defenders would be better, like you said.