A stoppage-time leveller saw Skegness Town held by Newark.
Jordan Smith gave the Lilywhites a 1-0 interval lead, finishing off a move involving Adam Millson and Conor Marshall.
Both sides had efforts ruled out and Town looked set to move up to fifth in the table before a 96th-minute equaliser from Brad McGregor.
Top-of-the-table Long Eaton were given a test by Sleaford Town, but left Eslaforde Park with three points.
The league leaders opened the scoring in the 25th minute as former Gainsborough Trinity striker Reco Fyfe's deflected effort found the net.
The Greens were level with 73 minutes played as Kyle Watkins' header found the net.
But six minutes later Kam Campbell settled it for United.
Boston Town were beaten 3-2 at Deeping Rangers.
The hosts took two-goal lead within the first five minutes courtesy of an individual effort from Marcus Pancho and Luke Steele's header.
But midway through the half Harry Limb pulled Boston back into the game as he found the net.
Abou Sylla levelled in the second half, but Deeping had the final say, Will Bird sliding home the winner.