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Powell struck twice inside the opening 16 minutes before Phillips and Matthew Pennington added two more goals before half-time.
Will Swan, George Lapslie and Phillips netted in the second half after Marine’s Isaac Abankwah was sent off.
Powell opened the scoring after 10 minutes with a first-time finish from Jayden Jackson’s cross.
And he struck again six minutes later when he headed home a Phillips cross.
Phillips finished well to make it three after Macaulay Gillespheys brilliant pass split open the Marine defence after 21 minutes.
Pennington put the game out of sight with a close-range finish after Phillips saw a shot blocked.
Abankwah conceded a penalty and was shown a straight red card after fouling Lapslie in the area after 54 minutes.
Jack McIntyre saved Lapslie’s spot-kick with his legs.
But the respite did not last long, with Swan making it five when he headed home Jackson’s cross four minutes later.
Lapslie added a sixth after Swan slipped him in before Phillips curled a beauty home to complete the rout with three minutes to go.