A goal from Fremantle's Justin Longmuir after the siren gave the Dockers a thrilling come-from-behind AFL victory over a depleted St Kilda outfit at Subiaco Oval.

The 12.8 (80) to 11.9 (75) win keeps alive Fremantle's flickering finals hopes, lifting them to 11-10 for the season and likely needing to beat Port Adelaide at AAMI Stadium next week to earn just the second post-season appearance in the club's history.

The Saints led by 16 points at three-quarter-time, but injuries to defenders Luke Penny (knee) and Matt Maguire (hip) and in-form big man Justin Koschitzke (quad) helped Fremantle run over the top of the visitors.

Add them to sidelined trio Max Hudghton, Xavier Clarke and Sam Fisher and the cupboard is starting to look decidedly bare for the Saints, who close its home-and-away season against Brisbane at the Telstra Dome.

St Kilda's top three chances have taken a hit and coach Grant Thomas has major defensive woes as he targets a breakthrough premiership win.

Saint Robert Harvey kicked the game's opening goal but the Dockers responded with the next four, with Matthew Pavlich and Luke McPharlin causing headaches for the depleted Saints defence.

Coleman Medal favourite Fraser Gehrig opened his account on the run in the opening term and Harvey added a second, but it was the Dockers that took a one-goal lead into the first break, their first lead in a Friday night game since defeating Melbourne in 1999.

Gehrig kicked his second goal early in the second to tie the scores before an arm-wrestle broke out, both teams going more than eight minutes without adding to the scoreboard.

Someone had to break the deadlock and the unlikely figure of Harvey stepped up to nail his third for the game to give St Kilda the lead.

Justin Peckett then got in on the action as St Kilda kicked three straight goals to wrest momentum from the home team.

Brought to you by AAP © 2024 AAP