Goals from Kenny Deuchar and Paul Murray gave Davie Irons' men the win, which keeps alive their slim hopes of avoiding relegation.
A succession of petty fouls proved to be the feature of the opening stages of the game which was being contested on a rock hard surface but a pattern quickly evolved as Gretna appeared to master the difficult conditions with greater ease than their visitors.
Gavin Skelton sent in a 20-yard shot in the seventh minute which tested Falkirk's Dutch goalkeeper Tim Krul.
An even better chance fell to Fabian Yantorno shortly afterwards, the Uruguayan midfielder firing his shot over the bar after an excellent cutback from Deuchar.
The main threat from Falkirk came via Pedro Moutinho on the left and the Portuguese wide man combined well with Dean Holden before his cross was headed wide by Carl Finnigan.
The Bairns then seemed to be taking control of the game when a Graham Barrett header brought out an outstanding save from Tony Caig in the Gretna goal.
But it was the home side who took the lead in 32 minutes, Yantorno's deep cross from the right being met by the unmarked Deuchar, who directed a powerful header beyond Krul.
Stunned by this setback, the Bairns finished the first half strongly with Finnigan evading three Gretna challenges before seeing his close-range shot blocked by Caig, then Holden headed narrowly from yet another superb cross by Moutinho.
A mere four minutes had elapsed after the interval when the Black and Whites increased their lead, Murray taking advantage of a misdirected defensive header by Falkirk captain Darren Barr before firing home a brilliantly struck shot from all of 30 yards.
Gretna held on easily for a comfortable win, which was marred slightly by an injury to Yantorno, who was stretchered off late on.