After just 41 seconds the visitors opened the scoring when Gary FletcherÂ’s left-wing cross was placed home by Paul Terry with his left foot giving keeper Danny Naisbitt no chance.
Conditions were wet and windy and players were often sliding over, this helped the lively forwards such as Junior Agogo, who after 15 minutes steered Mark Gower's corner over the bar.
Minutes later Agogo had a right-foot shot that went just wide of the post and left-back Lee Flynn tried a drive from 30 yards but his shot was well wide.
At the other end Daggers striker Junior McDougald broke through and Bees keeper Naisbitt has to race out of his area to partly clear the ball which ended up near the corner flag.
Naisbitt was then forced to concede a foul rather then let the striker shoot at the empty goal.
Dagenham seemed to be happy to play defensively and hold on to their one-goal advantage. This enabled John Doolan and Gower to take charge of the midfield and for Agogo and Wayne Purser to show their speed and test the visitors backline.
It was no surprise when Barnet equalised in the 31st minute when captain Greg Heald headed home Gower's cross from ten yards.
In the second half Dagenham's Danny Shipp was booked for a foul and three minutes later was given a second yellow card for kicking the ball away.
Dagenham side then played with a 5-3-1 line-up and were hard pressed to keep the Bees away from the goal.
It was no surprise when in the 94th minute of the game, loan signing Ian Hendon hit a 40-yard ball which Agogo controlled, before beating Tim Cole to score from ten yards.
The Bees deserved their win, but Dagenham had made them work for the three points.