Cavan minors came back from six points down to deservedly advance to their second Ulster final in three years with a classy attacking performance at the Athletic Grounds.
In an entertaining, free-flowing contest, Down went in at half-time holding a handy four-point lead, thanks to two identical goals.
Down opened the scoring three minutes in with a free from the lively Conor McCrickard but Cavan, who had ousted a fancied Monaghan in the quarter-final, hit back with points from Oisin Pierson and James Smith.
However, when Down galloped through the centre in the 12th minute and Ruairi McCrickard planted home a goal, the Mourne lads took the lead and, playing with a strong wind at their backs, they followed up with a second major eight minutes later, Liam Kerr this time providing a smart finish.
They tacked on another free from full-forward McCrickard before Cavan – who lost star midfielder Ronan Patterson to a black card 10 minutes before the break – finished the half strongly with points from Smith and a Patrick Lynch free to go in four down.
But the second half was all about the Blues, who were led brilliantly by Man of the Match James Smith. The powerful midfielder turned in an exhibition of high fielding and on this platform, Cavan built their second-half surge, with Pierson, Lynch and Cian Madden also sparkling.
Two super Madden points inside 90 seconds cut the deficit but a magical point from Kerr kept the James McCartan-managed Down in front.
Pierson, Seanie Keogan and Declan McClements traded scores next before Pierson curled in a free from the right wing to level it at 2-4 to 0-10.
A turning point arrived in the 42nd minute when Cavan goalkeeper Gary O’Rourke pulled off a smart save from Brendan Gallen – from the resulting counter, Pierson won a free, Lynch converted and Cavan grew in confidence.
Lynch and McCrickard exchanged frees but Cavan finally kicked for home and pulled clear with three well-worked scores in succession from Madden, Lynch and Pierson and when the latter fired over another sweet effort, Cavan were four up and cruising.
As the clock ticked down and Down pressed, they were forced into some last ditch defending but John Brady’s charges showed impressive maturity to hold possession and close it out to book their place in the provincial final against Derry.
Cavan: G O’Rourke, J Cooke, P Meade, K Brady, P Rogers, E Fortune, D Cusack, R Patterson, J Smith (0-2), K Hendrick, C Madden (0-3), O Kiernan, O Pierson (0-5, 1f), P Lynch (0-4, 3f), S Keogan (0-1)
Subs: K Cosgrove for Patterson (20 mins, BC), P Nulty for Fortune (45 mins), T Reilly for Cosgrove (54 mins)
Down: J Hazard, C Fitzsimons, B Gallen, T Gordon, F McElroy, P Fegan, S Annett, R McCormack (0-1), R McCrickard (1-0), R Anderson, C Clarke, D McClements (0-1), T Prenter, C McCrickard (0-4f), L Kerr (1-1)
Subs: L Middleton for Prenter (40 mins), R McEvoy for Anderson (54 mins), A Gribben for R McCrickard (54 mins), R Carr for McClements (57 mins)