Donegal prevailed in Ballybofey by 2-12 to 0-11
In the end, it was relatively routine work for Donegal but Fermanagh put up a stern resistance.
Goals either side of the half-time whistle from Odhran MacNiallis, sealed a comfortable win for Donegal, who lost resident defender Neil McGee to a red card in the first half. He now misses both the semi-final and the final.
McGee was adjudged to have connected with his elbow in a challenge, which led to a Fermanagh penalty and McGee's dismissal, but they were spared when Sean Quigley failed to convert the opportunity.
Fermanagh managed to stay within two points of Donegal on the stroke of half-time but couldn't keep pace with last year's Ulster finalists after the interval.
Tomas Corrigan slotted over an early free to bring them to within a point but that was as close as they got to Rory Gallagher's side as MacNiallis found the Fermanagh net for a second time inside the first fifteen minutes of the restart.
Some good interplay and swift transfer of possession resulted in the ball coming into the path of MacNiallis, who calmly palmed it into the net to leave the scoreline reading 2-07 to 0-08.
Donegal took the next two scores of the game, with Martin O'Reilly and the ever dependable Paddy McBrearty both swinging the ball over the bar. Fermanagh struggled to contribute to the scoreboard over the next fifteen minutes until a Tomas Corrigan free alleviated some of the pressure by bring the deficit down to seven points.
And Pete McGrath's side continued to press at Donegal but failed to break through the defences with the final score coming to 2-12 to 0-11.