After the opening four sets all went to tie-breaks, Colombian duo Farah and Cabal gained an advantage in the fifth and ultimately prevailed 6-7 (5-7) 7-6 (7-5) 7-6 (8-6) 6-7 (5-7) 6-3.
The match lasted four hours and 57 minutes while there was a delay when the roof was closed prior to the deciding set, and a finish of around 21:00 local time meant the scheduled women's doubles final had to be postponed until Monday (AEST), after Novak Djokovic and Roger Federer's men's singles showdown.
Defeat will bring back painful memories for Mahut, who famously lost 70-68 to John Isner in the final set of his first-round singles encounter at the All England Club in 2010, the longest match in open tennis history.
His partner Roger-Vasselin was in tears at the end and Mahut will be hurting in more ways than one after being struck three times during Sunday's (AEST) absorbing final in front of a captivated crowd.
The Frenchman required lengthy treatment after taking a blow to the forehead early in proceedings and was hit twice in successive points in the final set, once in the neck and then again in a more sensitive area.
He was unable to console himself with victory as Farah and Cabal became the first men from their country to win a grand slam doubles crown, both collapsing to the turf in delight as the championship point — the 419th point of the match — went their way.