Errigal Ciaran relied too much on current Red Hand ace Peter Harte, but had his first half penalty not come back off a post, the story of this tense Healy Park decider could have been captured in a totally different script.
The victors will face provincial champions Slaughtneil in their Ulster opener on Sunday week, with a revenge mission on their minds following a narrow final defeat in 2014.
Harte nudged Errigal ahead with a score inside the opening minute, but that was to prove their one and only score of the first half.
They could have had two goals, should have had at least one, but it was Omagh who controlled the play, moving confidently from deep to take the game to the men from Dunmoyle.
Barry Tierney got forward at every opportunity, and they crafted a goal chance when Micheal O’Neill sent Cormac O’Neill in, but his effort was cleared off the line by midfielder Ben McDonnell.
Errigal also had a goal opportunity, Harte’s superb pass sending Ronan McRory in, but he was denied by Niall McGinn’s superb save.
Omagh eased a head with scores from Connor O’Donnell, Conan Grugan, and Ronan O’Neill, but O’Neill was spared the cost of conceding a penalty when he impeded Mark Kavanagh in the 22nd minute.
Peter Harte, normally lethal from the spot, stepped up, but sent his kick crashing against the butt of a post, and a golden opportunity was lost.
Omagh pressed for the remainder of the half, and while they could only manage one score, a Grugan free, they were gradually taking control, with Conor Meyler and Barry Tierney raiding from deep, comfortable at 0-4 to 0-1 at the break.
O’Neill, Grugan, and O’Donnell found the range to keep Errigal at arms length, and Harte, along with sub Peter Óg McCartan, were left to carry the fight to the home side, but they went a man down following the second booking of Eoin Quinn, and were unable to recover after Omagh went four clear in the closing stages.
C Grugan (1f), R O’Neill (2f), C O’Donnell (1f) 0-3 each, J McMahon 0-1.
P Harte 0-5 (3f), P Og McCartan, D Canavan, R Lynch (f) 0-1 each.
N McGinn; G Murray, H Gallagher, S Mullan; C McLaughlin, J McMahon, B Tierney; C Clarke, M Gallagher; T Gallagher, C Grugan, R O’Neill; C O’Neill, C O’Donnell, C Meyler.
A Grugan for T Gallagher (40), A Grugan T Gallagher (40), Justin McMahon for Murray (60)
R McAnenly; N Kelly, A McCrory, C Quinn; M Kavanagh, M McRory, C McRory; B McDonnell, E Kelly, P Harte, E Quinn, R McRory, D Harte, P McGirr.
P Og McCartan for E Kelly (17), S McRory for McGirr (h-t), D Canavan for R McRory (h-t), D McDermott for M McRory (h-t), R Lynch for D Harte (52), P McAnenly for Kavanagh (55).
S Dorrity (Coalisland).