One Sunderland signing put in a brilliant showing for the U21s against Sheffield United. The Black Cats’ academy has been thriving in recent years, and the product is tangible with the likes of Chris Rigg and Dan Neil controlling the midfield for the first-team on a weekly basis. At just the age-of-17, Rigg is already being referred to as a generational talent, and Neil is leading out his boyhood club at 22-years-old, something that is a real testament to the Academy of Light and how brilliant it has been in producing brilliant talents over the years. The current U21 side is currently brimming…