Monaghan got a vital win in their bid for first division safety over a Roscommon side that had won all three of their opening games.
With 15 minutes to go, and three points between the teams in Monaghan's favour, Roscommon stalwart Diarmuid Murtagh was awarded a black card.
Rory Beggan extended the Monaghan lead moments later, and they managed to hold on for victory.
Jack McCarron (0-4) and Michael Bannigan (0-3) were on form for Monaghan while Ben O'Carroll, Ciaran and Diarmuid Murtagh and Richard Hughes all hit 0-2 each.
Full time score from Clones:
Monaghan 0-14 Roscommon 0-11.