Dartford closed the gap on the play-off pack as goals from Tom Bonner and Jacob Erskine earned victory at Braintree.
Bonner opened the scoring after converting Ryan Hayes' free-kick from inside the box.
Braintree's Brad Quinton brought a fine save from Marcus Bettinelli with a powerful free-kick while, at the other end, Tom Champion fired against a post.
Erskine doubled the visitors' advantage when he neatly headed Hayes' cross into the top corner from 12 yards.
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Braintree Town manager Alan Devonshire told BBC Essex:
"I thought it was men against boys. We know what they're about but they did a good job on us.
"We got done with two free headers. It was bad defending - as well as we defended on Saturday, that was kids' stuff.
"Maybe a couple of the lads mugged me off, saying they were OK after Saturday's game and I think some of them were struggling.
"They weren't honest with me and that's something I'll look at big time with regard to Saturday-Tuesday games. I'll probably make changes no matter what the scoreline is on the Saturday."
Dartford manager Tony Burman told BBC Radio Kent:
"This is a difficult place to come, I wanted the players to make sure they were right (after the draw at Wrexham) to come here and I thought we deserved to win.
"Braintree came back at us and we were a bit fortunate not to concede a goal.
"A few of them were running on empty with the games we've had so I'm delighted."