London Colney will travel to Brentwood in the first qualifying round of the FA Cup after they edged to a 2-1 win at Maldon & Tiptree on Saturday.
The Blueboys were missing Greg Shaw, Dan Power and Martin Collins but this did not stop them from taking the game to their Ryman League Division One North opponents.
London Colney opened the scoring after 27 minutes when Bobby Armstrong set up Jason Beck and he turned his marker before firing past the keeper from the edge of the area.
The visitors nearly doubled their lead from a James Lawrence free-kick but Sam Doolan's header was pushed onto the post by Jack Giddens' save.
Tom Smith also went close for the Blueboys but his 25-yard strike was kept out by keeper Giddens.
It looked like Colney would pay for these misses when Maldon equalised with just seven minutes remaining through Tony Martin.
But the visitors grabbed a winner three minutes from time when Harry Sedgley sent in a cross and Jimmy Hartley smashed home is effort from eight yards out.
London Colney host St Margaretsbury in the South Midlands Premier Division this Saturday.
The Blueboys Reserves were also winners after a 4-0 victory over Baldock Town following a brace from Sunny Farr and efforts from Daniel Lewis and Ed Frost.