Mark McLaughlin got too much on his header when Marco Paixao swung in a right-footed corner and Gallacher would have been relieved to see the ballflash a yard wide of his post.
Munster wing Anthony Horgan made a hash of collecting it and Flutey was onto the loose ball in a flash, avoiding O'Gara's desperate dive to streak away.
Boyd clipped the ball through the centre of the Celtic defence and Miller was onto it in a flash and showed great composure to roll it past the despairing Boruc.