Barry Lewtas' side showed great spirit and character as they fought hard in a physical away encounter.
The young Reds actually started brightly and Duncan fired a third minute opener, following a superb team move involving Elijah Dixon-Bonner and Fidel O'Rourke.
After the home side stormed back to a take a 2-1 half-time lead, Lewtas' side levelled when a Luis Longstaff cross was headed into his own net by the luckless Stoke defender.
Jack Bearne came off the bench to make it 3-2 and Duncan netted again to seal a good day's work for the U18s.