Shane Huke scored Dagenham & Redbridge's first away league goal to clinch their first away league win.
Town dominated but Michael Boulding had a shot saved by Tony Roberts, a header cleared off the line and missed two more chances before the interval.
After the break Dagenham scored with their first shot on target when Huke headed in Danny Foster's cross.
Matt Hamshaw and Boulding forced more saves from Roberts but Mansfield fell to a fifth successive defeat.
Mansfield: Muggleton, Mullins, Bell (Martin 84), Baptiste, Wood (Arnold 55), Hamshaw, Dawson, Buxton, Bullock, Boulding, McAliskey (Brown 68).
Subs Not Used: White, McAllister.
Dag & Red: Roberts, Foster , Smith, Uddin, Griffiths, Saunders, Huke, Southam, Rainford, Strevens, Moore (Sloma 46).
Subs Not Used: Thompson, Green, Taylor, Boardman.
Goals: Huke 63.
Ref: Andy Haines (Tyne & Wear).