With the 32-year-old Casemiro, you always must add the caveats. The problem is that football must be heartless and the quicker Manchester United can get Manuel Ugarte and his energy into that midfield the better. Asking 20-year-old debutant Toby Collyer and 19-year-old Kobbie Mainoo to stem that flowing Liverpool tide in the second half at Old Trafford was grotesquely unfair.