The Power honoured their former teammate John McCarthy with a 19.20 (134) to 11.12 (78) victory at AAMI Stadium.
Port vice-captain Brad Ebert epitomised a night of high emotion when, after kicking the match-sealing goal, he repeatedly kissed the black arm-band he wore in respect for his great mate McCarthy.
Moving tributes were held pre-match for McCarthy, who died at a Las Vegas casino complex last September while on an end of season trip with some Port Adelaide teammates.
McCarthy's Victorian-based family were among the 25,122-strong crowd, but the tearful tributes seemingly distracted Port players, who conceded four of the initial five goals.
But Port effectively settled the match with a 15 minute surge in the second quarter which reaped six consecutive goals.
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Utility Justin Westhoff was best afield with five goals, Chad Wingard booted three and experienced trio Ebert, Travis Boak and Kane Cornes formed a dominant midfield.
The Giants were well served by skipper Callan Ward and second-gamer Lachie Whitfield while Jeremy Cameron snared three goals.
Cameron kicked two of his majors early as GWS created a 21-point break just 22 minutes into the game.
Port reduced the margin to 11 points at quarter-time and then produced an unheralded second term scoring spree - in less than 14 minutes, the Power scored six goals and held GWS scoreless to take a 25-point break.
But GWS initially refused to buckle.
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They were helped in the third term when a wasteful Port logged seven consecutive points, but when the Giants' number one draft pick Whitfield kicked his first AFL goal, the visitors were just 13 points down.
But Port responded in style with eight consecutive goals - including Ebert's effort on the run early in the final term which triggered a wave of McCarthy-induced emotion.
Paul Stewart and Travis Boak celebrate a goal against GWS on Saturday night. Picture: AFL Media.
GWS 4.4 6.5 8.9 11.12 (78)
Port Adelaide: Westhoff 5, Wingard 3, Broadbent, Neade 2, Schulz, O'Shea, Boak, Hartlett, Stewart, Ebert, Mitchell
GWS: Cameron 3, Shiel, Giles, Coniglio, Patton, Whitfield, Treloar, Brogan, Smith
Port Adelaide: Westhoff, Wingard, Neade, Pittard, Cornes, Stevenson
GWS: Whitfield, Cameron, Ward, Shiel, Coniglio, Treloar
Port Adelaide: Hartlett (back), Schulz (ankle)
Port Adelaide: Kane Mitchell replaced Jay Schulz at three-quarter time.
GWS: Will Hoskin-Elliott replaced Stephen Gilham in the third quarter.
Umpires: Fila, Hay, Pannell
Official crowd: 25,122 at AAMI Stadium