Michael Harness scored the winner as Horncastle Town moved into the final four of the Supplementary Cup.
The Wongers are now into their second semi-final of the season, having already achieved similar success in the Challenge Cup.
Town hosted Lincoln United Development on Saturday, the only fixture involving Balcan Lighting Supplies Lincolnshire League teams to go ahead as the rain fell heavily across the county.
Player-manager Mickey Stones was also on target for the hosts at The Wong before Harness grabbed the winning goal in the 80th minute.
Cristovao Pissi scored for United.