AFC Sudbury became just the third side to lose to Ilford in Ryman One North this season.
Chinedu McKenzie scored the only goal of the game 19 minutes from time before Robbie Martin was sent off for foul and abusive language in the final few seconds.
Hadleigh United’s challenge for the Thurlow Nunn League Premier Division title appears to be over after a 2-0 defeat to Walsham-le-Willows.
In the First Division, Cornard United lost 3-1 at Downham Town, while Halstead Town saw off Debenham LC 3-0.
Long Melford’s trip to Whitton United fell victim to the weather.
In rugby, Sudbury slipped to second-bottom in London Three North East after a 25-19 reverse at home to leaders Norwich.