Second-half goals from Alan Massey and Liam Enver-Marum secured a comfortable win for Braintree at Dartford.
The Darts had the better of the first half but could not find a way past Braintree keeper Nathan McDonald.
Braintree improved after the break and the deadlock was broken in the 69th minute when Massey rose highest to nod in a free-kick from Kenny Davis.
And Enver-Marum wrapped up the victory for the Iron in the 90th minute when he tucked in a pass form Daniel Sparkes.
VIEW FROM THE DRESSING ROOM
Dartford manager Tony Burman told BBC Radio Kent:
"We didn't come out second half, we asked the guys for a bit of a response, it didn't happen.
"The longer the game went on we knew Braintree play a certain way, they want to play slowly but organised and we got caught up with the speed of the game.
"We have to be more intelligent and braver than we were in the second half."
Dartford 01 Julian 04 Stirling 05 Clarke Booked 14 Mitchell-King 06 Cornhill 08 Noble Booked (Woodyard - 86' ) 10 Bradbrook 20 Burns 07 Hayes (Collier - 86' ) 09 Prior (Harris - 71' ) 16 Birchall Booked Substitutes 24 Wellham 13 Rogers 15 Collier 30 Woodyard 11 Harris Braintree Town 01 McDonald 03 Habergham 05 Paine Booked 15 Massey 19 Wells 04 Isaac Booked (Carney - 90' ) 08 Davis 12 Daley (Sparkes - 66' ) 02 Peters 09 Marks 10 Holman (Marum - 75' ) Substitutes 20 Hamann 14 Carney 07 Symons 11 Sparkes 18 Marum