Youngsters make it three wins from three games
The win also marks the young Lilywhites third clean sheet in a row after beating neighbours Fleetwood 1-0, and Hartlepool 2-0 in the week's previous.
North End controlled proceedings throughout the 90, but it took until the 80th minute before they made their domiance count, with Barry converting Lamin Jagne's driven ball across goal and into the net.