It was a 58-point turnaround after the Power conceded an early lead to fall three points behind the Crows 14 minutes into the third quarter.
Four goals from Showdown 35 hero Chad Wingard, combined with a rampant second half up forward from Jay Schulz to seal the match and cap a day where the oldest club in South Australia came home to the place it won 21 premierships.
Championed by a sterling performance from eventual Showdown Medallist Hamish Hartlett, the Power stormed out of the blocks with the first three goals of the game, finding space wide and using the corridor to punish the Crows on several rebounding efforts.
Hartlett was in amongst it from the first bounce, with his trademark bursts through the pack crucial to so many of his club's forward movements.
He was ably helped by Brad Ebert who played a reliable and consistent game around the ground - an important link man on several occasions providing good support across the ground.
But the victors didn't have it all their own way, with the game threatening to turn into the Eddie Betts show after quarter time.
The ex-Blue tormented the Power with four goals - three in the second quarter - and looked menacing at deep forward.
Adelaide, as can be expected in Showdowns, came back hard after half time.
But the Power, through the spark of mercurial forward John Butcher, surged in the final moments of the term with exciting goals to Robbie Gray and Chad Wingard, combined with an after-siren major from Jay Schulz - eked out a five-goal lead at the final change which looked difficult to reel in.
It was, but only for the relentless running attack proffered by Port Adelaide for the remaining moments of the game that secured the historic victory.
That brave, risk-taking game play was praised by senior coach Ken Hinkley.
Port Adelaide's next game is against North Melbourne at Etihad Stadium on Sunday 6 April ahead of the club's next home match against the Brisbane Lions at the Adelaide Oval on April 12.
SCOREBOARD
PORT ADELAIDE 5.4 7.8 12.11 19.14 (128)
ADELAIDE CROWS 1.0 5.2 8.5 11.7 (73)
Goals
Wingard 4, Schulz 3, Gray, Wines, White 2, Boak, Ebert, Lobbe, Westhoff, Butcher, Hartlett
portadelaidefc.com.au's best
Hartlett, Ebert, Polec, Cornes, Broadbent, Hombsch, Wingard, Gray, Monfries
nil
nil
Showdown Medallist
Hamish Hartlett
Hamish Hartlett (19 votes), Brad Ebert (12), Jared Polec (3), Chad Wingard, Kane Cornes, Richard Douglas (ADL) (2), Eddie Betts (ADL) Brodie Smith (ADL) (1)
Crowd
50,397