Adebayo Akinfenwa's second-half goal earned Northampton victory and left Dagenham & Redbridge still seeking a first win of the season.
The Daggers edged an entertaining first half with Brian Woodall going close with a fierce shot and Lee Nicholls denying Medy Elito and Mike Spillane
Akinfenwa also was unlucky with a header at the other end.
And the big striker secured the points when he slid in to convert Chris Hackett's 67th minute cross.
Akinfenwa then came close to making it 2-0 in the 67th minute when he guided a header onto the post.
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Northampton Town manager Aidy Boothroyd told BBC Radio Northampton:
"We knew this was going to be a difficult game, particularly after the work that was put in on Saturday.
"I thought Adebayo Akinfenwa was very good and he played really well.
"The great thing is the variety that we've got (up front). He'll be the first to say it's all about the team and not about him. It isn't everything rested on his shoulders.
"Our record at home has been strong but you have got to win away - be dogged and defend for long periods - and we did that."