The leaders grabbed three points with a late Liam Tunstall winner against Horncastle Town, leaving them 10 points clear of Wyberton and Skegness Town, who won their top of the table clashes against Hykeham Town and Lincoln Railway AFC respectively.
It was a day dominated by home teams with bottom side Market Rasen Town picking up only their second league win of the season at home to CGB Humbertherm.
Brigg Town Reserves and Ruston Sports battled out a goalless draw.
In the Supplementary Cup Group A tie Cleethorpes Town Development Squad completed a quickfire double over Skegness United.
Results: Brigg Town Reserves 0 Ruston Sports 0, Market Rasen Town 3 CGB Humbertherm 2, Skegness Town 4 Lincoln Railway AFC 0, Sleaford Town Reserves 1 Horncastle Town 0, Wyberton 2 Hykeham Town 1. Supplementary Cup – Cleethorpes Town DS 3 Skegness United 1.