Two first half goals from Sligo's Mikey Gordon and Andy Kilcullen kept the game tight up until the latter stages, but it was Roscommon who pulled away to claim victory.
Paddy Fallon starred for Roscommon with 19 points on the evening.
Full time score from the University of Galway Connacht GAA Air Dome:
Roscommon 0-31 (31) Sligo 2-18 (24)