Accrington suffered a couple of late Daggers blows to the heart in a game of high drama at the Interlink Express Stadium.
John Coleman's team, without the suspended duo of Steve Halford and Peter Cavanagh, were undone by last minute strikes from Chris Moore and Kirk Jackson.
Indeed, Stanley also missed a penalty while the Lancastrians Robbie Williams proved he was no angel by being sent-off for a two-footed tackle on Mark Janney.
Striker Lutel James, recently at the centre of speculation about his future at the club, atoned for his first-half spot-kick miss after Tony Roberts had brought down John Mullin.
The former Bury marksman put Accrington into a 2-1 lead after Rory Prendergast had cancelled out a 13th minute opener from Chris Piper.
And James' 53rd minute strike looked likely to gain Accrington a Conference double over their London visitors.
The loss of Williams ten minutes from time didn't help their cause though Stanley hung on until those dramatic minutes.
Firstly, Moore equalised and then Jackson turned in a Leon Braithwaite cross. For Moore, it was his sixth goal in eight games while for 37-year-old Jackson it was his first since making the move from Yeovil.
And it was just the response Dagenham boss Garry Hill was looking for after his team's recent FA Trophy exit against Arlesey Town. For Coleman, the defeat was a major disappointment.
He'd described the game as "a massive one for us" and the loss certainly dented Stanley's play-off ambitions.