Adelaide has suffered a heavy 75-point loss to the Power at Adelaide Oval.
The Crows opened the scoring with the first two goals before Connor Rozee and Steven Motlop inspired a Power stampede that ended in a 17.8 (110) to 5.5 (35) thrashing.
Port – in the prison-bar strip – has now won three of the past five Showdowns, after having lost seven of the previous eight before its 57-point demolition of its arch-rival in round 16 last year.
The talented Rozee (eight clearances) was the early catalyst for Port, helping snatch the momentum midway through the opening term with his work in the clinches then capped it in front of goal.
Experienced pair Travis Boak (24 disposals) and Motlop (24) then took over to crush the Crows inside and outside the contest in a brutal display.
The Power lashed Adelaide after an even opening, kicking nine straight majors from early in the second term until ex-Magpie Ben Crocker finally snapped the streak shortly before three-quarter time.
The inside 50 count can be deceiving but not on this occasion. Each club had 13 in the first quarter but it was 47-22 in Port's favour by the final break, when the margin was 64 points.
Xavier Duursma chipped in with three goals and Zak Butters (21) was lively again, while Tom Rockliff (24), Hamish Hartlett (21) and Robbie Gray provided good support.
The other key instigator for Port Adelaide was developing key forward Todd Marshall.
Marshall was playing only his 22nd senior match but kicked two of the Power's four opening term goals and he set up another with a deep kick inside 50 after a strong mark.
The 21-year-old finished with 11 disposals, six marks, two goals and six score involvements and is fitting in beautifully next to Charlie Dixon in attack.
As if the result wasn't bad enough, Adelaide started the final quarter with only two fit players on the bench.
Captain Rory Sloane, who started brightly, had his right quadriceps on ice before three-quarter time, while defender Jake Kelly exited the match in the opening term with concussion.
However, Tom Doedee came through unscathed in his first outing since rupturing the anterior cruciate ligament in his left knee in round one last year.
PORT ADELAIDE 4.2 8.4 14.7 17.8 (110)
ADELAIDE 2.1 3.2 4.3 5.5 (35)
GOALS
Port Adelaide: Duursma 3, Dixon 3, Westhoff 3, Marshall 2, Motlop 2, Rozee, Butters, Ebert, Boak
Adelaide: Sloane, Fogarty, Smith, Crocker, B. Crouch
BEST
Port Adelaide: Rozee, Motlop, Boak, Duursma, Byrne-Jones, Butters
Adelaide: O'Brien, M. Crouch, B. Crouch, Talia
INJURIES
Port Adelaide: Burton (knee)
Adelaide: Kelly (concussion), Sloane (quadriceps)
