The Daggers left it desperately late, with Medy Elito grabbing the winning goal deep in injury time.
Few could argue they deserved the victory. For they had the lion’s share of the play and missed two glorious chances in the first half.
But they still owed a huge debt to keeper Chris Lewington, Who pulled off two outstanding saves as Rochdale threatened in quick breaks.
John Still’s men were on the front foot from the start, with Brian Woodall and Matt Saunders bringing Dale keeper Josh Lillis into action with shots he dealt with comfortably.
The Daggers called the shots through most of the first half. But the warning lights flashed when Dale were awarded a free kick 25 yards out and Bobby Grant brought a flying save from Lewington with a well struck effort.
Grant threatened again when he cut in from the right and let flk a left footer that had Lewington at full stretch to turn it over the bar and keep his team in the game.
But the best chances of the first half fell to the Daggers and Woodall will still be wondering how he managed to miss one in the 34th minute.
He was standing almost under the crossbar when a ball got through from the right. All it needed was a touch to put it in – yet he somehow managed to put it over the top, which seemed impossible to do.
Then, on the stroke of half time, Scott Doe met a free kick from Saunders from close in and put that one over the bar as well to complete a frustrating session.
Rochdale were much more of a threat after the interval. The stepped up the pace, were first to the ball and made much more of a match of it.
Ashley Grimes went close with an effort after the Daggers made life difficult for themselves by messing about in their own box. Andrew Tutte did get the ball in the net on the hour, but the effort was ruled out for offside.
And it seemed ominous when Dale did make the vital breakthrough in the 72 nd minute. Tutte pounced to fire into the roof of the net after Lewington had done well tp push away a deflected shot.
The lead lasted just two minutes as the Daggers hit back hard. Skipper Abu Ogogu – who won the man-of-the-match award put his team back in it by applying the finishing touch after lillis stopped a ball in from the right but was powerless to do anything about the follow up.
Still the Daggers hammered away and they got their reward in the second minute of added time when Sam Williams knocked the ball into the path of Elito, who calmly stroked it home to bring three vital points.
It was by no means a vintage performance. But the Daggers worked hard, refused to give in and got their reward.
Daggers: Lewington, Hoyte, Wilkinson, Doe, Ilesanmi, Ogogo ( C ), Saunders, Howell, Elito, Williams, Woodall. Unused Subs: Seabright, Spillane, Scott, Reed, Maher, Caprice, Bingham
Rochdale: Lillis, Bennet, Cavanagh ( C ), Barry-Murphy (Craney 86), Tutte, Grimes, Edwards, McIntyre, Pearson (Kennedy 65), Grant, Gornell. Unused Subs: Smith, Donnelly, Putterill, Adebola, Miniham.
Attendance 2289 (168 away supporters)