Port Adelaide have upset AFL ladder-leaders Geelong by 11 points to continue the Cats' post-bye curse.
The Power's rugged 9.13 (67) to 8.8 (56) win on Saturday night at Adelaide Oval is the eighth consecutive year Geelong have lost after a bye.
The Cats' second loss of the season was marred by the concussion of recruit Gary Rohan, who copped a head knock in an off-the-ball collision with Port's Karl Amon.
The Power's brilliant Robbie Gray was instrumental as Port rose to seventh on the ladder, leaving coach Ken Hinkley praising his players.
"Winning a close game against a high quality opponent ... it was wonderful for them to achieve the success they deserve," Hinkley said.
"They played a wonderful four quarters of football against a great side."
Gray and first-year forward Connor Rozee kicked two goals apiece and emerging midfielder Dan Houston gathered 26 disposals in the Power's seventh victory of the year.
Gray also collected 31 disposals, fellow veteran Travis Boak (30 touches) was valuable and Scott Lycett dominated the rucks with 41 hitouts, 24 disposals and nine clearances.
Port kicked the initial three goals of the game and controlled key statistics - they won the contested ball count by 36 and clearances by 16.
"The biggest problem was that margin around the stoppages," Geelong coach Chris Scott said.
Geelong's Patrick Dangerfield, after being a late arrival into Adelaide after the birth of his second child, a daughter, on Friday morning, was influential with 28 disposals.
His midfield colleague Mitch Duncan (35 touches) was a standout and Zach Tuohy (28 disposals) and Tom Stewart (23 possessions) marshalled Geelong's defence.
But the Cats struggled to find a forward-line winner - Gary Ablett and Darcy Fort booted two goals each - but Tom Hawkins was scoreless and blanketed by Port's Tom Clurey.
Geelong, in defender Harry Taylor's 250th AFL match, were within 11 points at three quarter-time.
But goals to Port's classy duo Rozee and Gray extended the home side's lead to 23 points early in the last - enough to hold off a belated challenge from the Cats, who kicked the last two goals.
Port's opening trio of goals featured a Charlie Dixon conversion in his first AFL game since breaking a leg more than 10 months ago.
The Power led 21-1 after Dixon's goal - for the rest of the game, the closest the Cats crept was within seven points early in the second stanza.