The U's were 4-3 winners at Victoria Road this afternoon, with goals from Dominic Vose (2), Macauley Bonne and Jabo Ibehre.
United had to fight back from being 3-1 down on the hour, despite taking an early lead. Trialist Darren Ambrose made a second appearance for the club and ex-Colchester players Mark Cousins, George Porter and Jamie Cureton featured for the Daggers.
U's: Lewington, Gordon, Eastman, Kent (Thompson), Clohessy, Eastmond, Ambrose (Moncur), Watt (Ibehre), Sears (Szmodics), Vose, Bonne (O'Donoghue).
Elsewhere, the U's under 21s won 4-0 at Bury Town, with Marcus Bean getting game time, having missed pre-season with a knee injury.