Cavan overturned a four-point half-time deficit to beat Armagh 0-12 to 1-6 and win their first Ulster Minor Championship title for 37 years.
Underdogs Cavan scored the first five points inside the opening 11 minutes at Clones but Armagh hit back with six points and a Paul McGeown goal.
Cavan did not score for 32 minutes but levelled with three quickfire points.
Andrew Graham edged them ahead and points from Nevin O'Donnell and Conor Finnegan saw them win by three.
"It was a brilliant second half. Our lads showed real guts," said Cavan joint manager Gary Donohoe.
"We had a good first 10 minutes and focused on that at half-time.
"We stuck at it and near the end we took our chances."
The game had an amazing sequence of scores with Cavan reeling off five, Armagh going four up and the winners then chalking up seven without reply.
Finnegan, Joe Dillon, Gerard Smith and two points from Andrew Graham got Cavan off to a flyer.
But Armagh hit back and were level after five points in five minutes through McGeown (2), Conor White, Ethan Rafferty and Conor McNally.
McGeown then netted the only goal of the game beforer Conor Gough added a point from play to leave Armagh 1-6 to 0-5 ahead at half-time.
The second half was scrappy and scoreless for 13 minutes but a Michael Argue score seemed to revive Cavan.
Darren McViddy fisted over to cut the gap to one after Davy O'Hagan had done brilliantly to save from Finnegan.
Captain Paul Graham pointed from play to level the contest and Cavan scored three more to clinch the Tom Markham Cup.