DONEGAL recovered from a poor start to secure the win by two points and maintain their divisional status for next season.
Corner-forward Lee Henderson was the hero for Donegal, hitting a total of 1-8, all coming in the second half.
For their part, Sligo will be disappointed to have lost the game given the fact they were so dominant in the opening half.
Sligo raced into a five-point lead after only 15 minutes with captain Keith Raymond banging over a succession of scores for the Connacht men.
Donegal looked like they had a mountain to climb but a goal from Ronan McDermott, with the full-forward reacting quickest in the large square, along with a brace of scores from Danny Cullen, brought them right back into the game.
Sligo added further points but had no answer to Donegal's dominance in the second half.
Man of the Match: L Henderson (Donegal)
SCORERS -- Donegal: L Henderson 1-8 (5f), R McDermott 1-0, D Cullen 0-2, N Campbell, J Boyle 0-1 each; Sligo: K Raymond 0-7 (7f), K Gilmartin 0-3, G Cadden (1f), M Burke 0-2 each, D Burke, A Cawley 0-1 each.
DONEGAL -- P Burns 7; P Doherty 7, C McLaughlin 6, E Organ 6; B Harrigan 7, J McGee 6, C McDermott 7; J Boyle 7, A McDermott 6; N Campbell 6, D Cullen 7, P Sheridan 6; L Henderson 9, R McDermott 7, M McGee 6. Subs: M McGrath for McLaughlin (45).
SLIGO -- D Loughnane 6; D O'Brien 5, D Tobin 6, T Cawley 6; J Kenny 6, B Kenny 7, E McGowan 6; A Cawley 6, T Conneely 6; K Gilmartin 8, K Raymond 8, D Burke 6; G Waldron 6, M Burke 7, L Cadden 6. Subs: R Cox for Kenny (14), G Cadden 7 for Waldron (47).
REF -- O Elliot (Antrim)