Cavan recorded a stunning 1-22 to 0-20 extra-time victory over a much fancied Derry side.
Derry had a couple of chances late in normal time to win the game but they failed to take them.
Late in extra time Cian Mackay, who had been substituted, and then came back into the game, scored the only goal to clinch a famous victory and set up a final qualifier against London or Mayo.
Derry got off to a fine start with three unanswered points but thereafter Cavan were the dominant side and led 0-09 to 0-07 at the break, with Martin Dunne (3) and Martin Reilly (2) their main scorers.
Fifteen minutes into the half Emmett McGuckin was hauled down in the goalmouth but inexplicably the referee who was well positioned to see the incident did not give Derry a penalty.
Cavan were the better side for much of the second half but a stunning display from Derry captain, 0-05 from 0-06, from frees brought the Oak Leaf County to the brink of victory.
But after a terrific 70 minutes Cavan levelled with the last kick of the game from Damian O’Reilly to force extra time
Derry really did not turn up in extra time as an eager and more determined Cavan took a grip on proceedings to lead at the break with three unanswered points.
Cavan controlled the pace of the game in the second period of added time and got their rewqard with Cian Mackay’s match-winning goal.
The Breffni County will now play the losers of Sunday's Connacht final where Mayo take on London.