SUPERSUB Michael McCrudden hit a 71st-minute winner 11 minutes after coming on to keep Newcastle top of Academy Group D.
The Irish midfielder drilled a low 17-yard shot across Forest keeper Karl Darlow into the bottom left corner after Nile Ranger turned a left-wing Shane Ferguson cross back into his path.
The fourth successive win was fair reward for United's youngsters who were made to battle hard for victory but were well worth the points.
Ameobi never deserved a goal more than in the 65th minute when he ended a strong run with a 30-yard rocket that Darlow, diving full-length, tipped on to his left post and behind.
In the first half Ameobi had twice been denied by Darlow, while James Tavernier, Ranger and James Taylor all fired chances straight at the keeper.
However, McCrudden's goal finally tipped the scales and thereafter United comfortably held Forest at bay to cement top spot.
NEWCASTLE UNITED UNDER-18s: Alnwick; Taylor (McCrudden 60), Lough, Tavernier, Morris, Kadar, Newton, Inman, Ranger, Ameobi, Ferguson. Subs (not used): Leadbitter, Neary, Bath.