Retford booked their place in the next round of the FA Vase, after a late rally saw them beat Shirebrook Town 3-1 on Saturday.
United will visit Oadby Town in the next round on 4th October, thanks to the first qualifying round victory at the Jones and Co Stadium.
The opening half an hour saw no clear chances for either side, only Sam O’Malley putting the ball across the United goal causing a scare but none of his teammates were there.
With the first half almost over, Leigh Hutchinson played the ball in for Reece Thompson but it went out of play before he could connect.
It was a poor first half for both sides, but the NCEL Division One were the happier of the two going in goalless.
Retford started brightly in the second period, a corner won by Thompson bobbled in the area with Jack Steadman’s shot blocked by the outstretched leg of a defender.
Liam Nelthorpe sent the ball to the far post with Hutchinson rising to power a header only a fraction wide of the upright.
The game looked certain to be going into extra time, but the breakthrough came on 74 minutes when Jamie York’s shot from the left beat Fuller at full stretch to put Shirebrook ahead.
The lead only lasted five minutes, as replacement Ben Muirhead played in Hutchinson who did well to stretch and poke the ball past the keeper with Thompson slotting home under pressure from a defender.
On 85 minutes Retford took the lead as a corner by Muirhead was met by Hutchinson who rose to head the ball past the keeper.
The win was finally secured in the 90th minute with Nelthorpe’s strike from Thompsons cross found the target and put Retford into the next round.
United return to league action on Saturday at home to Maltby Main.