Play was held up for 10 minutes in the first quarter on Sunday at Cockburn before Swans ruck Caitlin Reid was stretchered from the field.
She was felled by a clash of heads with Fremantle's Hayley Miller.
After Sydney rallied in the second half and took the lead, Miller snapped a goal to bring the Dockers to within one point and Wharfie Time was sounded, with less than 90 seconds on the clock.
But just as the crowd activation backfired horribly in the AFL grand final loss to Brisbane, the Dockers could not score again.
Chloe Molloy took a game-saving mark with 15 seconds left and the Swans won 5.7 (37) to 5.6 (36), denying Dockers star Ash Brazill a farewell win.
Molloy kicked four goals to break the AFLW goalkicking record with 28, two up on Hawthorn's Aine McDonagh and Geelong forward Jackie Perry. Sydney racked up nine wins, a club record.
"It's a good catapult ... into the finals, close wins like that," Molloy told Fox Footy.
"It always brings out a bit extra energy, especially when you hear Wharfie Time."
Geelong will host Melbourne, followed by reigning premiers North Melbourne against Carlton in a qualifying-final double header next Saturday afternoon at Ikon Park.
Sydney expect to pack out Henson Park on Sunday against the Bulldogs, before Gold Coast host Hawthorn in the other elimination final.
Earlier on Sunday, Melbourne overcame Adelaide by 18 points despite an injury concern to star Kate Hore.
At a wet Unley Oval on Sunday, the Demons claimed a third consecutive victory and ended their regular season 10-2 by prevailing 6.11 (47) to 3.11 (29).
But they may have to sweat on midfielder Hore, who was left holding her shoulder after Jemmika Douglas bumped her in the dying minutes of the clash.
Tyla Hanks insists their captain will be fine for next week's final against the high-flying Geelong, telling the Seven Network the four-time All-Australian is "pretty tough".
Demons coach Tom Wilson said Hore was "fine".
"Any time you see a player go down like that your heart is in your mouth a little bit, but the good news is that she's all OK," Wilson said.
The Dees were without several players, including star midfielder Olivia Purcell (managed), emerging ruck Georgia Campbell (illness) and Shelley Heath-Barker (concussion).
Melbourne were virtually locked into third going into the clash, but knew a victory would be crucial as they look to avenge last year's finish.
The Demons finished second on the ladder in 2025, but lost in the first week of finals then exited the competition at the preliminary-final stage after North Melbourne produced a fourth-quarter clinic.
The Demons were strong from the outset on Sunday as they dominated first-half clearances to open up a 25-point lead at the main break.
Forward Ryleigh Wotherspoon booted two majors in the second half to put the result beyond doubt, although Adelaide salvaged some pride by kicking the last goal.
For Melbourne, midfielders Megan Fitzsimon (one goal) and Hanks were busy registering 26 and 29 disposals respectively.
Ebony Marinoff (34 disposals, 11 tackles, eight clearances) excelled once again for the Crows, although they will hope Caitlin Gould's foot injury isn't serious after she stepped awkwardly while trying to grasp the ball and hobbled off the field in the third term.
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