It was a matched littered with errors and neither team looked comfortable, but two goals in the second half killed the game off for the Daggers.
Dagenham started the better of the two teams and almost opened up the home defence after just five minutes but Craig Mackail-Smith failed to find Tresor Kandol after getting into the area.
The home team began to have meaningful possession and in the 14th minute Altrincham played a one-two with Chris Adams down the left flank and from the full-back's cross a shot was acrobatically saved by Dagenham keeper Tony Roberts.
But Dagenham took the lead nine minutes before half time. Glen Southam found space on the left-hand side and his cross was finished by Kandol, heading out of Stuart Coburn's reach into the bottom corner of the net.
Altrincham made a spirited start to the second half but two quick goals from Dagenham soon put paid to any resistance.
First Chris Moore received a short free-kick from Southam on the edge of the area before blasting a left footed shot past Coburn, then Jake Leberl capitalised on an error by the keeper, knocking the ball into the net after he had met a cross from Moore.
The fourth goal came in bizarre circumstances when Coburn handled outside his area and while the keeper was waiting to receive a yellow card, Moore put in a free-kick for Kandol to head into the empty net.
Mackail-Smith rounded of the scoring with an unstoppable shot from the right-hand side of the area but the final scoreline was particularly harsh on the home team.