Rowan Alexander's men weren't at their best but started well enough. Chris Innes headed over the top from a Steve Tosh corner and David Nicholls tried his luck from range before Kenny Deuchar latched onto Todd Lumsden's slack back-pass to fire home his 24th goal of the season.
Lumsden made amends before half-time blocking a Deuchar shot on the goal-line and heading a fierce effort from John O'Neil over the bar.
Raith's battling brought dividends when Chris Silvestro grabbed the equaliser placing a shot past Alan Main when Paul McManus cut back the ball from the byline.
And Rovers could have gone in front two minutes later but Main blocked from Laurie Ellis after Innes played his back-pass short.
But man-of-the-match Gavin Skelton restored Gretna's lead in the 74th minute. David Graham sent Ryan McGuffie down the right flank and he crossed for Skelton to fire in at the second attempt after Alistair Brown had blocked his first shot.
James Grady almost made it three when he turned past two markers to hammer a shot past Brown only for it to come back off the inside of the post.
Brown produced a great save to turn Tosh's goal-bound effort round the post late on and former Queen of the South man Emilio Jaconelli came close at the other end with an overhead kick that flew over the bar but Gretna were not going to be outdone and the party started when the final whistle blew.