The hosts went ahead late in the first half but there was an immediate reply from Boro with an equaliser by Chris Taylor from George Tubey's cross and a bending shot from George Woodward into the far corner.
Seven Acre levelled in the second half but Romford won it two minutes from time with a goal from sub Joe Tingey.
Team: Atu Ngoy, George Tubey, Sam Burton, Harry Cullham, George Woodward, Reece Cosson, Ollie Smith, Chris Barry, Chris Taylor, Ryan Imbert, Joe Bricknell
Subs: Jake Giddings, Joe Tingey, Joe Scott, Bradley Morgan