Donegal Celtic will go into the promotion/relegation play-off series after securing a nervous victory over Dungannon Swifts at Celtic Park on Tuesday night.
Celtic must await to find out who their play-off opponents will be after this result, coupled with Lisburn Distillery's defeat to Ballymena United, sent the Whites into the Championship.
Two first-half goals were enough for Pat McAllister's men but they were forced to dig deep and defend it in a second-half dominated by weakened visitors, who threatened to nick a late equaliser with a flurry of attacks.
The hosts, battered at this venue only last Saturday by Ballymena United, took a 10th minute lead through defender Mark Burns who rose to meet Kevin Keegan's corner but only after former DC keeper Tuda Murphy let the ball slip from his grasp.
Dungannon, starting without the likes of Stefan Lavery, Ryan O'Neill, Johnny Montgomery and James Costello, engineered a threat on the Celtic goalmouth in the 28th minute when Chris Lavery saw his close-range header, from Matt Hazley's corner, cleared off the goal-line. From the resultant corner, Hazley rifled a volley just wide of John Connolly's goal.
But it was Celtic who would find the target in response. The diminutive Ryan Deans' relentless work when a cause seemed to be lost, saw the midfielder send in a perfect cross for the awaiting Kevin Hughes to nod past Murphy in the 37th minute.
Then the test of nerve came when Hazley's 51st minute low cross into a crowded goalmouth appeared to go in off Celtic defender Pat McShane.
Celtic were thankful when veteran keeper Connolly brilliantly denied Adam McMinn an injury-time leveller.
Donegal Celtic: Connolly, Keegan, Bradley, C Burns, M Burns, McShane, Carson, Deans (McCann 66), Devine (McAreavey 61), Hughes (Downey 75), O'Neill
Dungannon Swifts: Murphy, Grieve (Magee 16), McMinn, Hutchinson, PJ Lavery, Douglas (S Lavery 68), Hazley, Glackin (O'Neill 77), McKerr, Brennan, C Lavery.
Referee: Hugh Carville (Belfast).