A contentious goal from striker Pawel Abbott saw Darlington record a valuable 1-0 away victory over fellow promotion contenders Dagenham.
Abbott latched on to a long ball over the top after 74 minutes, and with Daggers screaming for an offside call, he confidently tucked his shot under Tony Roberts.
Defeat was harsh on the home side as they had the ball in the net twice in the opening half.
Paul Benson saw his first effort ruled out for offside, before referee Iain Williamson ruled out a second Benson strike for an alleged push.
Ben Strevens also came close late in the game but his fierce shot flew wide of the post.