The result moved the Cobblers out of the bottom two, three points clear of danger, ahead of the final game with Chris Wilder’s old club Oxford.
Dagenham could not create any clear-cut opportunities early on and they were to rue their lack of creativity. Ivan Toney, 18, scored his first Northampton goal in the eighth minute – expertly heading home an Ian Morris cross.
Just four minutes later, that advantage was doubled. Morris lashed home a spectacular volley from 25 yards after Dagenham had failed to clear a Chris Hackett corner.
And Toney doubled his tally for the afternoon five minutes before the break with a quite exquisite finish. Darren Carter’s corner was half cleared by Brian Saah to Toney, who deftly controlled the ball and hit an unstoppable overhead kick beyond the reach of Dagenham goalkeeper Jordan Seabright.
Both Saah and John Marquis had goals ruled out for offside either side of half-time.