A thrilling second-half performance at Croke Park, lit up by the majesty of Cormac Costello, eased holders Dublin to their first win in the Allianz football league.
Beaten in Monaghan six days ago, Jim Gavin's All-Ireland winners were under pressure initially here in front of 14,502 before hitting their straps.
They led by just a point at half-time but outscored Galway by 1-9 to 0-2 in the second-half to inflict their third consecutive defeat on Kevin Walsh's side in under a year.
Costello scored six points in total and claimed the Man of the Match award while Dean Rock hit 1-5 including the 55th minute goal that sealed the win.
Mannion had a strong game up front too while Footballer of the Year Brian Fenton dominated the midfield.
Dublin hadn't ever previously lost back to back games under Gavin in the league or Championship, a record they've now extended to 93 games.
They struggled initially with Galway and didn't take the lead until the 30th minute when Rock clipped a trademark free over.
Costello and Shane Walsh traded scores before the break and Dublin led by just 0-6 to 0-5 but there was only one team in it after the resumption.
Galway only managed two points in the entire second-half and were rocked by the loss of Cillian McDaid with a foot injury.
The former U-21 star who returned from the AFL last autumn kicked two first-half points before being replaced.
Galway badly missed his drive and determination in the second-half and with the Corofin players also absent they were burned off by a Dublin side that upped the ante considerably.
Rock and Costello both enjoyed bursts of scoring in the third quarter before Rock seized on a Paul Flynn ball in to claim possession and beat the 'keeper at the near post.
Suddenly Dublin led 1-11 to 0-6 and Gavin could afford to roll in all his talented substitutes knowing the game was up for Galway.
Darren Gavin came on to make his league debut while Ryan Basquel, Liam Flatman and Sean Bugler, who scored a point, all enjoyed full league debuts by lining out.
Dublin scorers: D Rock 1-5 (2f), C Costello 0-6 (1m), P Mannion 0-2, Sean Bugler, N Scully (1m) 0-1 each.
Galway scorers: P Cooke, C McDaid 0-2 each, J Heaney, B McHugh (1f), S Walsh (1f) 0-1 each.
Dublin: E Comerford; E Lowndes, M Fitzsimons, L Flatman; E Murchan, J Cooper, J Small; J McCarthy, B Fenton; N Scully, C Costello, S Bugler; R Basquel, P Mannion, D Rock.
Subs: B Howard for Basquel 48, P Flynn for Bugler 55, J McCaffrey for Small 60, D Gavin for McCarthy 61, C McHugh for Mannion 66.
Galway: M Breathnach; G Bradshaw, S Kelly, E Kerin; G O'Donnell, SA O Ceallaigh, J Heaney; K Duggan, T Flynn; C McDaid, J Duane, P Cooke; P Cunningham, C D'Arcy, S Walsh.
Dubs: B McHugh (0-1, 1f) for McDaid h/t, F Cooney for D'Arcy 60, D Cummins for Cunningham 61, G Armstrong for Cooke 62, D Cunnane for O Ceallaigh 67.
Ref: C Branagan (Down).