NEWCASTLE stretched their unbeaten run to eight games, but for the fourth match running conceded a goal in the last five minutes.
Substitute Ryan Markey struck at the death after United had been two up.
The home side took an interval lead when Aron Spear found the corner of the net and the lead was doubled nine minutes into the second period via Brandon Meile’s 22-yard drive.
Darragh Reynor reduced the deficit from the spot and Forest equalised following a quick injury time free-kick, Markey eventually finding the net.
NEWCASTLE UNITED UNDER-18s: Alnwick, Nicholson, Toland, Sayer, Storey, Mogwo, Spear, Meile, Taylor, McGorrigan, Knight. Subs: Ions, Mitchell (gk), Evans, Turton, Smith.