The centre-back headed the Robins into a 17th-minute lead only for Sido Jombati to score a bizarre own goal to level four minutes later, the defender curling a back pass beyond debutant goalkeeper Connor Roberts from 25 yards.
Cheltenham went ahead again on 24 minutes when a Matt Richards effort was deflected over visiting keeper Jordan Seabright.
But it was all square once more a minute before the interval when a deep free-kick from the visitors picked out Scott Doe, who slotted home at the far post,.
The Robins dominated after the break but Jombati had an effort headed off the line by Daggers skipper Abu Ogogo.
And, with their first chance of the second period, the visitors grabbed the winner when Adebayo Azeez turned the loose ball home after a Gavin Hoyte effort had been pushed onto the post by Roberts.