The Dockers finals hopes have been dashed by a last minute goal from the Saints Josh Bruce to go down by three-points.
Fremantle dominated periods of the game and looked more likely than the Saints to grab the points in 10.12.72 to 10.9.69 loss.
It was a frantic final minute of the game as the Saints charged forward to find Bruce 35-metres out from goal.
Dockers skipper Nat Fyfe couldn't have done much more claiming 35-disposals and booting two majors.
Brandon Matera also kicked two goals in his side's losing performance.
Coach Ross Lyon said he couldn't doubt his group and their effort.
"Of course we're frustrated. We invest a lot. I would think our finals opportunities close," Lyon said.
"But to come interstate, really compete like we did, I can't really question the effort … Of course I'm frustrated."
The Dockers are back at home taking on Essendon next weekend.