Barry McHugh and Damien Comer scored 0-7 between them as Galway made it five wins from five at Monaghan's expense in Salthill.
Monaghan, who arrived at Pearse Stadium on the back of a three-matchwinning run, paid the price for playing over half of the game with 14 men after Fintan Kelly was red-carded for kicking out at Galway defender Eoghan Kerin in the 33th minute. The hosts' were trailing by 0-5 to 0-7 at that stage, but made the most of their numerical advantage to score the next six points and take control of the game.
Kieran Hughes pulled back a goal in injury-time for Malachy O'Rourke's men, but it was a case of too little, too late as Galway effectively sealed their place in the Division 1 final.
Two Barry McHugh frees and points from play by Paul Conroy and Damien Comer helped the home side to an early 0-4 to 0-2 lead, but Monaghan grabbed five of the next points to go two up after 30 minutes. The pick of their scores during this fine period of dominance were two superb long-range efforts by Kieran Hughes.
However, the game took a decisive turn in Galway's favour when Kelly needlessly kicked Kerin in the backafter he had been fouled by the defender. His 'moment of madness' led to the 30-metre free being reversed as the visitors missed the chance to go three points clear.
Monaghan still led by two points at the interval, but the Tribesmen never looked back after Damien Comer kicked the first of six unanswered points which propelled them into a four-point lead after 50 minutes.Shane Walsh, Barry McHugh (two), Eamonn Brannigan, and substitute Adrian Varley were the other scorers during this spell.
The table-toppershad stretched their advantage to seven points before Hughes fielded a high ball and finished to the net in stoppage-time to put a better complexion on the scoreline from a Monaghan perspective.
Galway - R Lavelle; D Kyne, S A O Ceallaigh, E Kerin; G O'Donnell, G Bradshaw, C Sweeney; P Conroy (0-2), C Duggan; J Heaney (0-2), S Walsh (0-1), E Brannigan (0-1); P Sweeney, D Comer (0-3), B McHugh (0-5f). Subs: S Armstrong (0-1f) for P Sweeney, P Cooke for C Duggan, A Varley (0-2) for S Walsh, S Kelly for G O'Donnell, T Flynn for J Heaney, F Burke for B McHugh.
Monaghan - R Beggan (0-1'45); R Wylie, K Duffy, C Boyle; K O'Connell, P McGuirk, V Corey; K Hughes (1-3), N Kearns; R McAnespie, F Kelly, N McAdam; C McManus (0-4, 3f), J McCarron (0-2, 1f), M Bannigan. Subs: C McCarthy for J McCarron, D Ward for M Bannigan, D Wylie for P McGuirk, D Hughes for N McAdam, O Duffy for V Corey.
Referee - B Cassidy.