Chris Moore hit a brace as Dagenham came from behind to win easily.
Rovers took an early lead when Charlie Griffin headed in a Scott Rogers cross, but the Daggers were level when Moore converted a John Taylor pass.
And just after the break the visitors took the lead with Lee Flynn scoring from a free-kick after Jimmy Turner had fouled Mark Janney.
Moore hit made it three before Glen Southam completed the rout with a fourth with 10 minutes remaining.
Forest Green: Perrin, Green (Marvin Brown 69), Gadsby, Turner, Davies, Holloway, Rogers (Cleverley 69), Cowe, Sykes, Griffin, Beesley (Danks 69). Subs Not Used: Greaves, Bown.
Booked: Turner, Gadsby.
Goals: Griffin 3.
Dag & Red: Roberts, Goodwin, Cole, Uddin, Vickers, Janney, Southam, Leberl, Flynn (Griffiths 90),
Taylor (Mackail-Smith 85), Moore. Subs Not Used: Baruwa, Blackett, Hill.
Booked: Vickers, Southam.
Goals: Moore 30, Flynn 49, Moore 61, Southam
Ref: A Dewfield (Hinckely).