The young Magpies, who reached the final of last year's competition before suffering a 3-2 loss against Blyth Spartans at St. James' Park, conceded twice in the opening 45 minutes following Lewis Orrell's long-range drive and Andrei Ardelean's tap-in.

Michael Ndiweni's close-range finish halved the deficit for United's youngsters in the closing stages before Malcolm Morien's emphatic effort from distance confirmed the Seahorses' passage into the semi-finals.

After facing Crystal Palace in the Premier League Cup on Monday night, Elliott Dickman made eleven changes to the side which suffered a 1-0 defeat against the Eagles' second-string, with the likes of left-back Matt Bondswell - who featured for the Magpies' first-team during pre-season friendlies against Benfica, Atalanta and Athletic Club - named in the starting line-up as well as striker Cameron Ferguson, son of former Magpies forward Duncan.

In front of 629 spectators, Newcastle goalkeeper Max Thompson - a representative of England at under-18 level - was forced into early action as the 18-year-old, who joined United's Academy at the age of 11, kept out Harvey Neary's powerful effort, holding the winger's attempt.

The United 'keeper, who kept a clean sheet on his Young Lions debut against Russia in October 2021, then beat away Josh Gilchrist's stinging strike as the former Newcastle youth product picked the ball up in a dangerous position after the Magpies defence were unable to clear the ball to safety.

Ferguson went narrowly close to netting his first goal of the 2022/23 campaign at under-21 level as the Liverpool-born forward met Jamie Miley's inviting corner before his header was cleared off the line by Elliott Day, situated on the back post.

In the 20th minute, Whitley Bay opened the scoring as the ball fell kindly to Orrell on the edge of the box before the midfielder was able to slam an effort through a crowded penalty area into the far left-hand corner.

Ndiweni almost drew United level shortly after as the Throckley-born striker connected with Kyle Crossley's in-swinging cross from the left flank but his golabound header was importantly pushed away by Nash.

In the 31st minute, Newcastle were dealt a further blow as Ardelean doubled the Seahorses' lead as Neary's initial strike was parried by Thompson into the path of the Bay striker, who bundled the ball into the net inside the six-yard area.

Newcastle introduced the likes of Joe White, Dylan Stephenson and Jay Turner-Cooke in the second-half in the hope of salvaging a fightback, with the latter testing Nash with a low strike from the edge of the penalty area, comfortably held by the hosts' shot-stopper.

In the 72nd minute, Newcastle set up a tense finale as Ndiweni was on hand to tuck the ball from close-range after Diallo's cross-cum shot was parried kindly into the 18-year-old's path.

With the full-time whistle approaching, Diallo almost levelled the tie as the 19-year-old winger, who joined the Magpies in October following a successful trial, struck a teasing effort from the right flank, forcing Nash to push the ball out for a corner.

In the 90th minute, Whitley Bay confirmed the victory through Morien's audacious effort as the Bay substitute picked the ball up from distance before firing a speculative effort beyond Thompson into the top right-hand corner.

Newcastle United Under-21s: Max Thompson, Josh Stewart (Joe White 71), Charlie Wiggett, Nathan Carlyon, Matt Bondswell, Jamie Miley, Amadou Diallo, Josh Scott, Michael Ndiweni, Kyle Crossley (Jay Turner-Cooke 55), Cameron Ferguson (Dylan Stephenson 55).

Subs not used: Harry Barclay, Will Brown.