Hall Farm moved into third place in the table, handing a rare defeat to long-time leaders Durham City Reserves.
The Sunderland side have enjoyed an excellent campaign in the new league, and they edged all three points thanks to a strike from defender Darren Cessford.
Michael Renshaw was their star man, with Adam Crathoren best for City.
Durham’s lead is seven points from second-top Redcar Town, who have five games in hand.
Hall Farm are third, nine behind City with an extra match to play.
It was the only league game to beat the rain, though one cup tie also got the go-ahead.
Coundon & Leeholme made good progress in the South Durham Bowl, securing a 3-1 second round success at Bishop Auckland Welcome Tavern, from the Crook and District League. Paul Bailes and two-goal man of the match Kurt Matthews did the damage.