Full-back Richard Rose scored an injury-time winner as Dartford beat early-season Blue Square Bet Premier pacesetters Newport County.
The hosts took the lead when Harry Crawford nodded in after Jacob Erskine's header hit the bar.
Newport hit back five minutes after the home side's 49th-minute opener as Aaron O'Connor rounded goalkeeer Marcus Bettinelli to level the score.
But Rose's 18-yard strike secured a fourth straight win for the hosts.
VIEW FROM THE DRESSING ROOM
Newport manager Justin Edinburgh told BBC Radio Wales:
"I think we were naïve, really. We dominated the game and, certainly if we'd left with a point, it would have been the least we'd have deserved.
"But we've left here with nothing and probably of our own doing. I am really so disappointed with that.
"But again, we're learning all the time about the group and how they haven't been able to see a game out, which is disappointing."