The young Magpies took a deserved first-half lead at the VBS Commnity Stadium, home of National League side Sutton United, courtesy of Anthony Munda's impressive header after guiding the ball home from Alex Murphy's inviting cross.
United's second-string doubled their advantage after the hour mark through Joe Brayson's clinical finish as Adam Lawrence's side secured maximum points on a productive evening in South London.
After a dominant spell of possession in the opening stages, Newcastle went close to taking the lead as Seung-soo Park, who arrived at the Magpies from K League 2 side Suwong Bluewings last summer, ran onto Alex Murphy's dangerous pass down the left flank but after dangerously cutting inside, the Korean winger's powerful drive at goal was held by Palace goalkeeper Harry Lee.
Alfie Harrison, who has recorded four assists in his opening six league games at under-21 level, almost got off the mark in front of goal this term as the Keighley-born teenager latched onto Brayson's inviting lay-off inside the box before his vicious first-time effort was blocked by the head of Eagles skipper Luke Browne.
Newcastle's youngsters took the lead in the 20th minute through Munda's first goal of the 2025/26 campaign at second-string level. After Park and Murphy combined neatly on the left wing, the latter's inviting cross found Munda inside the box, who placed a terrific header into the left-hand corner.
The visitors survived a dangerous attack shortly after as Zach Marsh beat Magpies goalkeeper Max Thompson to a loose ball inside the penalty area but, situated in a tight angle, the centre-forward could only square the ball into the six-yard area, with Newcastle defender Miodrag Pivaš winning possession inside the box.
Brayson, who scored ten league goals at under-18 level last term, was unable to double the Magpies' lead as the 18-year-old striker raced onto Munda's pass after the Cowgate-born midfielder initially intercepted Lee's attempted clearance, but Browne was on hand to turn the ball onto Brayson before the ball ricocheted into the hands of Lee.
Munda, who signed his first professional contract for his boyhood club in the summer of 2024, almost scored his and United's second goal of the evening on the stroke of half-time as the 19-year-old controlled Leo Shahar's lofted pass into the box before, with time and space, his fierce drive at goal was pushed away by Lee.
Sean Neave went close to netting a seventh goal of the season at under-21 level as the Winlaton-born forward, named on the bench for Newcastle's Carabao Cup final victory against Liverpool in March, completed a positive run towards goal before his drilled effort was pushed over the bar by Lee.
Newcastle extended their lead in the 65th minute through Brayson as the teenage striker, on target in Newcastle's UEFA Youth League defeat against Benfica last week, controlled Neave's pass inside the box before directing a firm low effort into the far corner via the right-hand post.
Thompson produced a key save to preserve United's two-goal cushion shortly after as the Ponteland-born goalkeeper, who spent the 2024/25 season on loan at League Two side Chesterfield, held Benjamin Casey's header after a dangerous cross into the penalty area.
Park was unable to net his first goal in a Magpies shirt as the highly-rated 18-year-old, who made his full debut for Eddie Howe's side during a pre-season friendly against RCD Espanyol at St. James' Park in August, controlled Harrison's pass before his delayed shot at goal was blocked out for a corner.
Newcastle's youngsters, however, comfortably saw out the league encounter to record their first clean sheet of the current campaign, moving within three points of the division's top 16 spots.
Newcastle United Under-21s: Max Thompson, Leo Shahar, Alex Murphy (Charlie McArthur 74), Cathal Heffernan (c), Miodrag Pivaš, Scott Bailey, Alfie Harrison, Anthony Munda, Joe Brayson (Dylan Charlton 82), Sean Neave (Ciaran Thompson 85), Seung-soo Park (Kacey Wooster 82).
Subs not used: James Taylor.
