NEWCASTLE United needed extra time to overcome battling Grimsby Town and book their place in the fifth round of the FA Youth Cup.
Ben Sayer chipped home the winner late in extra time in a close contest at St James’ Park to set up a last-16 trip to Manchester United.
Marcus Maddison went close twice for United in the opening 15 minutes. Ryan McGorrigan was then slipped in by Dennis Knight but steered his shot wide from 10 yards.
Maddison then cleverly turned Josh Marshall on 34 minutes but screwed his shot just wide.
Maddison caused havoc again with another burst, and eventually Aaron Spear applied a close-range finish at the Leazes End on 45 minutes.
On the hour, Grimsby’s Sam Mulready earned his side a penalty when he collided with Alnwick.
Alnwick saved from Ryan O’Loughlin by diving low to his left.
However, Mulready scored five minutes later when his angled shot skidded beneath Alnwick.
That forced extra time, and Ben Sayer grabbed the glory with a neatly dispatched chip over Rob Peat eight minutes from time.
NEWCASTLE: Alnwick, Nicholson, Riley, Sayer, Streete, Storey, Spear (Campbell 71), Nzuzi, McCorrigan (Mogwo 116), Knight (Hoganson 71), Maddison.