Luke Guttridge's Golden Goal fired Cambridge United into the Southern Area semi-finals of the LDV Vans Trophy at Luton Town.
The Cambridge midfielder fired past an exposed Mark Ovendale to win the tie 2-1 in the second half of extra time.
Guttridge's 113th minute effort was only Cambridge's second shot on target of the evening and Shaun Marshall shared hero status with his matchwinning team-mate after a string of impressive saves to deny the Second Division Hatters.
Home striker Tony Thorpe had earlier given the home side a 14th minute lead with his fifth goal of the season.
But Terry Fleming equalised on 57 minutes to send the tie into extra time.