Two goals in as many minutes from David Rainford and Glen Southam gave the Daggers a 2-0 half-time lead and matters only got worse for the hosts after interval as Sam Saunders, Paul Benson and Craig Mackail-Smith all netted to send their side home happy.
Chasing their third win in as many home games, Altrincham could not have got off to a worse start.
In the 11th minute Saunders floated a corner over from the right flank and while the home defence dallied, Rainford's shot from the edge of the area was deflected into the corner of the net by Gary Scott.
But lessons went unlearnt by Altrincham and their troubles were quickly compounded when Dagenham scored their second just a minute later. More woeful defending saw the Robins fail to clear a seemingly innocuous through ball and Southam popped up in exactly the same position as Rainford to shoot confidently past Stuart Coburn.
The home side barely managed to gain a foothold in the game, but did at least threaten to score twice just after the half hour mark. A throughball from Steve Aspinall sent Colin Little in behind the defence and although he skipped around the onrushing Tony Roberts, he was forced too wide.
The striker managed to pull the ball back to Steve Bushell and Roberts clambered across his goal to make a last-gasp save.
As Alty kept their visitors on the back foot, Robbie Lawton flashed the ball right across the face of goal, but a lunging Warren Peyton just failed to connect at the far post.
Straight after the interval, Altrincham looked slightly more assured. They soaked up their fair share of pressure but did begin to break out themselves a little more often.
Little twice came close, first being denied by the outstretched leg of Jake Leberl after taking down an Aspinall cross and then firing narrowly wide after scrapping his way past Anwar Uddin.
But just as the Robins began to sense they might have a chance, it all went horribly wrong with 23 minutes to go.
Mackail-Smith caught the home defence out on the break and although he was unceremoniously halted by Bushell, the ball ran to Benson on the edge of the area. His shot then crashed against the bar but Saunders was on hand to blast in the rebound.
Dagenham added another four minutes later after Scott gave the ball away cheaply. Mackail-Smith was denied by Coburn but Benson was on hand this time to put away the loose ball.
To add insult to injury, Dagenham scored their third goal in a seven-minute second-half blitz when Sam Sloma crossed and Mackail-Smith headed home to complete the result.