And the victory lifted the Whites back into the play-off places, leaving the O`s in sixteenth place.
Dover were the first to threaten when an effort from Ade Azeez was blocked by Ebou Adams.
Josh Koroma`s free-kick at the other end was well saved by Mitch Walker and from the resulting corner, Craig Clay`s header was blocked by Nortei Nortey.
Walker was in action again on 35 minutes when he held a Macauley Bonne header.
And then the home side had a chance right at the end of the half when Azeez fired over the bar after the ball had fell kindly to him in the box.
Shortly after the break, the home side`s Giancarlo Gallifuoco forced Dean Brill into his first serious save of the afternoon from his header.
And at the other end, Dan Holman`s shot went narrowly wide.
Then on the hour-mark, the majority in the 1,348 crowd thought their side had taken the lead when a rebound following a free-kick fell to Nortey, whose effort crashed against the post and was cleared.
Koroma forced a save from Walker at the other end with another well-taken free-kick and then it was the O`s turn to hit the woodwork from a Lamar Reynolds shot.
But on 83 minutes, the deadlock was finally broken when the lively Azeez set up Mitchell Pinnock (pictured) to drive past Brill.
Josh Coulson fired wide as the visitors searched for an equaliser, but the Whites held firm to reward all concerned with three hard-earned points.