Dartford 1 Charlton Athletic 0
Mohamed Eisa's 90th-minute free-kick sent Dartford through to the Kent Senior Cup quarter-finals at the expense of holders Charlton.
The tie seemed destined for extra-time but the Addicks were left to rue a series of missed opportunities when Eisa curled a terrific set-piece beyond the reach of goalkeeper Dillon Phillips.
There was no time for Charlton to grab an equaliser and the Darts will now host Dover Athletic in the last-eight.
Youth was the focus at Princes Park, with just four senior players in Dartford's starting XI and only one of those - midfielder Max Cornhill - having started Saturday's league game at Hereford.
Charlton's team was also full of youngsters. Diego Poyet, the teenage son of new Sunderland manager Gus, played in their midfield.
The first half was largely uninspiring.
Jack Munns side-footed over from 20 yards and Kadell Daniel's miscued shot almost found a way into the net when it cannoned off Dartford defender Jay Porter.
Charlton enjoyed the lion's share of possession but Harry Gerard's shot which hit the roof of the stand summed up the general quality of play.
When a long ball forward caught out Ronnie Vint, Toby Sho-Silva should have put Charlton ahead, but he snatched at his effort and the ball flew wide.
Dartford barely had a sight of the Charlton goal in the first 45 minutes but they should have been in front less than 60 seconds after the restart.
Porter turned his man inside-out and picked out Ryan Hayes with an inch-perfect cross from the left. The goal seemed to be gaping but Hayes' header lacked direction, bouncing down into the turf before looping up over the crossbar.
Charlton skipper Bradley Jordan sent one shot whistling past the base of the post and blazed another wastefully over after Harry Osborne's right-wing cross had found its way to his feet.
Darts keeper Deren Ibrahim then pulled off a string of excellent saves to thwart the Addicks as they turned up the pressure.
Ibrahim got a strong hand to Osborne's low shot and then turned Munns' powerful drive over the bar from close-range.
A free-kick from George Monger was headed awkwardly wide by Josh Hill, but the majority of play was taking place in Dartford's defensive third.
Osborne poked a weak shot across the face of goal after working himself a yard of space and Daniel drilled a shot wide after running purposefully across the face of the box.
Daniel turned an Osborne cross goalwards but he found Ibrahim in good form yet again. Daniel then tried his luck from a free-kick, targeting a hole in the Dartford wall, only to see the ball to fly wide.
A Harry Lennon volley flashed narrowly past the post and it seemed only a matter of time before the visitors would finally get their noses in front.
But the Darts refused to roll over, with Vint standing tall in central defence alongside Hill, who is likely to play some role against Hyde in the Skrill Premier on Saturday.
At the other end, Eisa set up Uche Ibemere for a shot which flashed wide.
But the deadlock was finally broken as the clock ticked past 90 minutes. Femi Akinwande's positive driving run from the left wing drew a foul just outside the box and Eisa stepped up to send Dartford through.
Dartford: Ibrahim, Allen, Hill, Vint, Porter, Hayes (Akinwande 60mins), Cornhill (Fry 46mins), Monger, Eisa, Da Silva (Adams 70mins), Ibemere. Subs not used: Scantlebury, Worfold.
Charlton: Phillips, Holmes-Dennis, Feely, Lennon, Daniel, Sho-Silva, Osborne, Gerard (Ahearne-Grant 88mins), Poyet, Jordan, Munns. Subs not used: Muldoon, Barnes, Gomez, Thomas.
KENT SENIOR CUP QUARTER-FINAL DRAW
Bromley v Hythe Town
Whitstable Town v Maidstone United
Tunbridge Wells v Ebbsfleet United
Dartford v Dover Athletic
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