Roscommon fell to a seven point defeat in Pearse Stadium to fall into the Allianz League division one relegation places.
The win puts Galway in with a real chance of making the league final, Roscommon need to beat Kerry in Dr. Hyde Park to have any chance of staying up.
Galway’s Johnny Heaney’s shot crashed back off the post after seven minutes but Gareth Bradshaw scored off the rebound to put two points ahead.
Anthony Cunningham’s side played well into the wind and their kick passing into space was causing problems for the Galway defence.
Points from Enda Smith Tadhg O’Rourke levelled matters, before Antaine Ó Laoi put Galway a point ahead before Ciaran Duggan also got his name on the scoresheet for the home side, and despite a rare score from Conor Daly, Galway started to pull clear.
Shane Walsh curled over a point to put Galway five points to three clear, while Gary O’Donnell stretched their lead soon after.
Two minutes before the break Cummins found the net after John Daly’s smart pass, which gave his side a 1-11 to 0-07 lead at half time.
Galway started the second half brightly when John Daly and Walsh points, but after a Colm Lavin 45, Roscommon were thrown a lifeline when Shane Killorna’s shot was stopped with a foot block
Conor Cox converted the penalty to give the Rossies hope.
Galway responded with a free from Ó Laoí after Conor Daly pulled down Walsh, while Roscommon began to find scoring difficult at the other end and their wides tally hit double figures.
Niall Daly was black carded late on as Roscommon finished with 14 players as Galway sealed a 1-17 to 1-10 lead.