Josh Abe and Josh Sonni-Lambie scored during a five-minute spell prior to the half-hour mark to put the Reds in command.
Matthew Taylor responded for the hosts to set up a decisive final 20 minutes, though it elapsed without further goals.
The home team enjoyed more of the early chances, with Bailey Hall making a save from a Taylor strike on eight minutes.
But a fruitful period of play for Simon Wiles’ visitors sent them into a strong advantage midway through the half.
First, Sonni-Lambie set up Abe to open the scoring by finding the bottom corner from inside the box.
After Sonni-Lambie and Joe Upton fired efforts on target from long range, the Reds then doubled their new lead.
This time, it was Sonni-Lambie who beat Magpies goalkeeper George Mair, converting with a right-footer from outside the area.
The home team were having the majority of the possession but attempts were coming freely at either end.
And Sonni-Lambie was so close to making it three for Liverpool just past the hour, hitting the post.
Taylor had been at the heart of much of Newcastle’s attacking threat and he reduced their deficit 20 minutes from the end.
Found by Henry Johnson, he beat Hall with a header from the middle of the box.
Haydn Murray-Holme was sent off for a second yellow card in stoppage time but the Reds held firm in the remainder to take victory, with Hall saving from Matheos Ferreira deep into the added minutes.
They are, though, eliminated from the group stage, having finished third in Group B.
Team
Hall, O’Connor, C. Williams (Ayman, 64), Cisse, Owen, Upton (Hickman, 71), Abe, Murray-Holme, Sonni-Lambie, Farkas (Hawkins, 82), Lee Forrester (Inglethorpe, 71).
Unused sub: Bernard.
Next up
The Reds’ U19s are in UEFA Youth League action on Wednesday (November 26), hosting PSV Eindhoven.
Kick-off at the Kirkby Academy is 2pm GMT and the game will be shown live on All Red Video for members.
