Back-to-back wins for the first time this season lifted the Daggers out of the dreaded League One drop zone, writes Jack Steggles.
An early goal from Bas Savage settled the game, gave the Daggers three more precious points and sent Colchester back up the A12 empty handed.
John Still's men have battled their way out of the bottom four but know they still have a lot of work to do to ensure survival in League One.
But after this hard earned result confidence is high and the Daggers are clearly ready from the challenge that lies ahead.
They proved that by digging in to knock a hole in Colchester's hopes of making the play-offs in a rousing Essex derby.
Savage has found goal hard to come by - but he must enjoy playing against Colchester. He scored against them in the 2-2 draw on their ground earlier in the season and did it again here to bring his tally for the season to three.
He was on the spot to apply the finishing touch with a low shot from close range after the impressive Romain Vincelot won the ball in an 11th minute penalty area tussle.
Danny Green had tried his luck with a free kick in the opening minute - lashing a shot from out on the left over the bar in an ambitious attempt.
Ian Henderson tossed away a glorious chance to equalise in the 20th minute, when he was left with a clear shooting chance from 15 yards after the Daggers failed to get the ball away.
But he let the home side off the hook by dragging his shot wide of the near post with a poor finish.
Green also failed to get a clean strike when a great ball from Solomon Taiwo found him clear on the right. He hit it first time but topped the shot, which went wide.
Colchester did get the ball in the net in the 28th minute, but it was ruled out for offside. Their best effort came from Andy Bond, a cracking 20 yard beaten away by Tony Roberts.
Colchester rang the changes in the second half in a bid to get something from the game, but they produced little to worry Roberts.
Their best chance of the second half fell to Anthony Wordsworth, who scooped a shot on to the roof of the net.
With the Daggers worrying record of conceding goals late in the game the nerve ends jangled as the minutes ticked away.
But they remained solid, gave nothing away and can look back on a tricky job well done as they sent the fans home happy.