Fremantle has sewn up a top four spot and the double chance with an eight-point win over Port Adelaide at Subiaco Oval.
The Power pushed the home side hard in the first two and a half quarters, but the Dockers kicked clear in the second half before withstanding a late comeback from the visitors to win by 16.9 (105) to 14.13 (97) win.
Port Adelaide missed a series of early chances, but kicked three first-quarter goals to be level with the Dockers at quarter-time.
Both sides kicked four goals apiece in the second term as the visitors went in with a one-point buffer at the main break.
The Power then silenced the vocal home crowd with two early goals in the third term to Jay Schulz and Hamish Hartlett, before the Dockers finally clicked, booting six goals without reply to take a 22-point lead into the final quarter.
Goals to David Mundy and Hayden Ballantyne looked to have sealed the win for Fremantle, who led by 38 points at the 12-minute mark.
But the Power fought back again to get within nine points in the final minute before Justin Westhoff missed a meaningless kick after the siren to leave the final margin at eight.
For Fremantle, small forwards Hayden Ballantyne and Michael Walters kicked four and three goals respectively, while Schulz led the way for the visitors with a six-goal haul.
The Dockers will travel to play either Sydney or Hawthorn in a qualifying final next weekend, while Port Adelaide will host an elimination final at Adelaide Oval.
More to follow.