St Eunan's set up an Ulster Club SFC semi-final against Omagh next weekend as their first-half domination led to Sunday's six-point victory over Roslea.
With Kevin Rafferty outstanding, Eunan's moved 0-5 to 0-0 ahead and Conal Dunne then added a penalty before the break as Roslea remained scoreless.
Seamus Quigley opened Roslea's account in the 40th minute but there was never any prospect of a comeback.
Roslea cut the margin to six but Eunan's had already done their job.
Dunne finished with a tally of 1-4 while veteran John Haran and Donegal star Rory Kavanagh also starred for the Letterkenny club.
On home territory, St Eunan's went into the game as favourites but the paucity of the Roslea challenge for most of the contest was something of a surprise.
Roslea's defensive approach early on, as they had 13 men behind the ball on occasions, appeared to hinder themselves more than Eunan's and when the ball was delivered to the Quigley brothers Seamus and Sean in attack, they were hopelessly outnumbered.
The Donegal champions were boosted by the availability of impressive midfielder Rafferty who had been expected to miss out after sustaining a cut in last weekend's county final win over Glenswilly.
Rafferty fired over the opening point in the sixth minute and his good work set up two further points for Dunne by the 13th minute.
Two more Dunne points increased the advantage to five by the 20th minute and the killer blow was then delivered to the Fermanagh champions in first-half injury time as Dunne coolly slotted a penalty after Roslea back James McMahon had pulled Haran's jersey.
After a lull in proceedings, Seamus Quigley finally registered Roslea's first score on 40 minutes but Eunan's hit back with three unanswered scores.
As the Letterkenny side took their foot off the gas, Roslea hit five unanswered points to cut the margin to six but they outcome had long since been decided.
Rafferty capped his fine individual display with St Eunan's final point on 56 minutes and not even the score of the match as Seamus Quigley notched a beauty with the outside of his right boot could mask a disappointing afternoon for the Fermanagh champions.
SUNDAY'S ULSTER CLUB SFC
SLAUGHTNEIL 0-11 0-09 CAVAN GAELS
ST EUNAN'S 1-09 0-06 ROSLEA