Cavan pulled off an amazing comeback at Brewster Park to progress to the second round of the All-Ireland qualifiers.
The Breffni men were six points down with 20 minutes left but responded with 3-03 in the space of 10 minutes, including goals from Gearoid McKiernan, Niall McDermott and Eugene Keating.
Fermanagh had foraged into a 0-08 to 0-05 interval lead and they widened the margin to six - mainly thanks to Daniel Kille (0-09) - until Cavan hit back decisively.
Cavan produced a stunning comeback to stun hosts Fermanagh and win their first senior championship match since 2010.
The Breffni men hit 3-03 in a devastating 10-minute spell to completely turn this All-Ireland first round qualifier on its head after it looked like Fermanagh would win pulling up.
The home side led by six points after 50 minutes and were in total control, watched by an attendance of 5,260.
However, Peter Canavan's side only scored two points during the remainder as Cavan blitzed them with 2-02 inside four minutes to spark the fightback with goals from Gearoid McKiernan and Niall McDermott.
Trailing by 0-13 to 0-07 to a rampant Fermanagh, it looked like it was going to be another tame exit from the qualifiers for Cavan, who had not won a SFC tie since beating Wicklow in the qualifiers two years ago.
The Ernesiders had foraged into a 0-08 to 0-05 interval lead and they widened the margin to six - mainly thanks to top scorer Daniel Kille (0-09) - until Cavan hit back decisively.
But from the moment McKiernan hit the net in the 51st minute, this Ulster derby was turned on its head. If Cavan were going to win anywhere, it was going to be in Brewster Park - the scene of both their Ulster Under-21 final victories in the past two seasons.
Many of those underage stars were on the pitch today, with McKiernan and Jack Brady leading the fight. McKiernan scored the all-important first goal and set up the others for McDermott and Eugene Keating.
Corner forward Kille hit eight of his points from frees and was unlucky to be on the losing side. His free on the hour mark looked like it had stopped the rot after the crazy 2-02 they shipped in four minutes.
Yet within 20 seconds, the ball was in the back of their net for a third time. Keating, the man who scored 0-05 from play against Donegal last time out, drilled a third goal past Ronan Gallagher to seal an astonishing comeback for Cavan.
After the first goal went in, Cavan’s players visibly grew in self belief but Fermanagh went into their shell, similar to their collapse in the Division 4 final defeat to Wicklow earlier this year.
It gave Cavan an extra reason to cheer, with the announcement that Seanie Johnston's Kildare had been beaten at Croke Park ironically being read out over the PA just before the Breffni fightback began.
Cavan started taking chances they had been missing earlier. They kicked 15 wides to Fermanagh's five over the 70 minutes.
The loss of David Givney towards the end of the first half looked like it was another blow they were going to have to absorb, but once the first goal went in their body language changed.
The Fermanagh defence parted straight down the middle. The loss of the suspended Daryl Keenan, sent-off in the defeat to Down, as well as the injury to Ryan McCluskey and absence of enigma Seamus Quigley, proved too much in the end.
Kevin Tierney could have hit them for a fourth goal late on only for a good save by Fermanagh goalkeeper Gallagher, who really could not have been faulted for any of the goals.
FERMANAGH: R Gallagher; B Cox, B Owens, J Woods; N McGovern, B Mulrone, C Quigley; S Lyons, R Jones (0-01); E Donnelly, S McCabe, T McElroy; T Corrigan (0-03), P Ward (0-02, 0-01f), D Kille (0-09, 0-08f).
Subs used: D McCusker for McElroy (52 mins), M McGrath for Cox (54), Sean Quigley for Ward, M Jones for C Quigley (both 63), P Cosgrove for Mulrone (68).
CAVAN: B McVeigh; D Tighe, K Clarke, P O’Reilly; M McKeever, F Flanagan, D Reilly (0-01); D Givney, T Corr (0-01); R Flanagan, G McKiernan (1-01), N Smith (0-01); N McDermott (1-01, 0-01f), E Keating (1-01), J Brady (0-05, 0-02f).
Subs used: K Tierney (0-01) for Givney (35 mins), J McLoughlin for Clarke (half-time), D McKiernan (0-01) for McKeever (46), K Meehan for Smith (67).
Referee: Barry Cassidy (Derry)