Yet the game could have been so different with Rovers going in front after just nine minutes. Lee Phillips' ball forward was flicked on by Steve Cowe sending Alex Meechan clean through before slotting the ball past Fleet keeper Paul Wilkerson.
Gravesend could have equalised eight minutes later. Ben Abbey's through ball intended for Steve Perkins was only cleared as far as Roy Essandoh, but his tame shot was comfortable for Steve Perrin to stop.
Two minutes before the interval another opportunity came the visitors' way when a short corner was then swung into the box by Steve McKimm, only for Chris Moore to head over the crossbar.
Forest Green had a chance to double their lead in first-half injury time. Martin Foster's deep cross was headed down by Cowe but Scott Rogers' attempted volley went high and wide of the target.
In the second half Gravesend looked for the equaliser and were inches away ten minutes after the interval when McKimm's direct free-kick from just outside the area went inches wide of the upright.
Against the run of play, Rovers' Foster sent a low ball across the face of the Gravesend goal, but Cowe and Gareth Stoker were unable to connect, and able to give Rovers the two-goal cushion they needed.
In the 69th minute Gravesend equalised and Forest Green had only themselves to blame, with poor defending allowing Perkins' cross from the right to find Essendoh at the back post, unmarked to head the ball into the opposite corner of the net.
Six minutes later, Stoker gave the ball away and McKimm's low drive was only parried by Perrin and Essendoh again was on hand to stick the loose ball away to win Gravesend the match.