Two quickfire early strikes from Keanan Bennetts and Reo Griffiths put Spurs 2-0 up inside the opening ten minutes at St. James' Park.

Dave Watson's side rallied and reduced the deficit thanks to Lewis McNall's penalty after the break, but Kazaiah Sterling's low drive put the visitors 3-1 up.

An incredible final ten minutes saw McNall pull another back from close range, before Japhet Tanganga made it 4-2.

But after Owen Gallacher had given Newcastle further hope by nodding in to make it 4-3, substitute Dylan Duncan curled home at the death to clinch the victory in front of a crowd of 2,847 and send John McDermott's side into the last four of the competition.

The visitors got off to the perfect start, as winger Bennetts cut in from the left and, after a dazzling stepover or two, unleashed a ferocious drive that left goalkeeper Nathan Harker helpless as it flew just inside the right-hand post.

And less than five minutes later, Watson's youngsters went two down. Harker spilled a cross on the byline and, though skipper Owen Bailey produced an outstanding block to deny Tashan Oakley-Boothe, Griffiths latched on to the loose ball to find the bottom corner and leave Newcastle with a mountain to climb.

Bennetts - who would come off injured moments later - could have made it three before the half hour when he was played in by George Marsh, but his left-footed cross-shot sailed past Harker's post and United survived.

Newcastle did come close to pulling one back before the break, though, as McNall flashed a powerful shot just past the upright and Lewis Gibson nodded an Adam Wilson corner wide. Matty Longstaff then sent in a teasing cross, but the Magpies couldn't apply a finishing touch as they ended the half with a spell of pressure.

And just five minutes after the restart, they earned themselves a lifeline. Gallacher's pace and persistance on the left took him into the box and, when he cut inside, he was tripped by Marsh. McNall stepped up to send Brandon Austin the wrong way from the spot, maintaining his record of scoring in every FA Youth Cup tie this season and giving his side hope in the process.

Skipper Owen Bailey then saw an attempt blocked as the hosts continued to press, but with their first attack of the second period, Spurs extended their lead against the run of play. Substitute Kazaiah Sterling, on for the injured Bennetts, turned and fired low beyond Harker from just outside the box to restore Spurs' two-goal advantage.

Bailey headed a Longstaff free kick just wide of the target soon after, and McNall's emphatic finish from close range made it 3-2 just before Tanganga looked to have put the result beyond doubt, smashing home at the other end.

But just seconds after the restart, a fine cross from Ben Kitchen found Gallacher, who headed in to set up a thrilling finale.

When substitute Mackenzie Heaney floated an inch-perfect cross into the box moments later, Bailey thought he'd snatched a dramatic equaliser as his diving header made its way towards the bottom corner, but goalkeeper Austin got a fingertip to the ball at full stretch to deny him in the most dramatic fashion.

Right at the death, though, Spurs clinched it. Another replacement, Duncan, rounded off a thrilling contest by curling past Harker into the top corner at the Leazes End to book his side's place in the last four of the competition.

Newcastle United Under-18s: Nathan Harker; Ben Kitchen, Owen Bailey (c), Lewis Gibson, Kieren Aplin; Matty Longstaff, Mace Goodridge (Mackenzie Heaney 77); Owen Gallacher, Thomas Allan (Callum Smith 67), Adam Wilson; Lewis McNall.

Subs not used: Otto Huuhtanen, Lewis Cass, Kelland Watts.

Tottenham Hotspur Under-18s: Brandon Austin, Timothy Eyoma, Nick Tsaroulla, George Marsh (c), Jonathan Dinzeyi, Japhet Tanganga, Samuel Shashoua, Oliver Skipp, Reo Griffiths (Dylan Duncan 72), Tashan Oakley-Boothe, Keanan Bennetts (Kazaiah Sterling 29).

Subs not used: Tariq Hinds, Alfie Whiteman, Jack Roles.

Referee: David Webb

Bookings: Newcastle United Under-18s - Matty Longstaff (81); Tottenham Hotspur Under-18s - none