Peter Brabrook's boys reached the last four of the FA Premier Youth Academy knock-out stage thanks to a 2-1 victory over their north London rivals, despite going a goal down in the first half.
They drew level after the break when Billy Mehmet skipped down the flank and crossed for Darryl McMahon (pictured above) to score from eight yards out.
They snatched the winner when James Allen crossed from the right and Mehmet's first time effort flew into the net from 10 yards out.
Elliot Ward was a hero late on as he cleared an effort off the line with just two minutes left.
The semi-final will be against Ipswich Town and takes place at Chadwell Heath next Saturday (May 12), kick-off 11am.
The game was watched by Tony Carr, while Paul Heffer took charge of the under-19s, who beat Bristol City 4-1 with a brace each from Foyewa and Morris.
Under-17s team: Jackson, Khan, Dean, Ward, Tattum, Cascione, D.McMahon, Mehmet, Eastwood, Allen, Ritchie. Unused subs: G.Sealey, A.Ferdinand, Pearson, Fletcher, M.Cole.
Under-19s team: J.Sealey, Clark, Riddle, Uddin, Laurie, Smith, Britton, Saunders, Foyewa, Morris, Akinsette.