John McCombe scrambled home a late equaliser to deny Conference South outfit Dartford a place in the second round of the FA Cup and spare Port Vale's blushes in a 1-1 draw.
Market researcher Elliot Bradbrook looked to have done enough for the Darts to sink their League Two opponents when he converted Ryan Hayes' 39th-minute free-kick.
But McCombe, who had twice cleared Dartford efforts off the line in the first-half, tucked in Tommy Fraser's corner with six minutes left.
Danny Harris almost gave the Darts a dream start when he fired past Stuart Tomlinson in the fifth minute only for defender McCombe to hack the ball off the line.
The Kent side reached the first round for the first time in 21 years but they dealt comfortably with their League Two opponents in the first half and, after warning strikes from Carl Rook and Paul Goodacre, took a deserved lead.
The excellent Hayes curled in a free-kick which skipper Bradbrook fired home from close range for his third goal of the season.
Vale boss Micky Adams responded by making three changes after the break and the visitors finally paid off when McCombe headed home.