FREMANTLE knows it will be in a scrap to hold onto its top-four spot but is not concerned that Sydney's tactics in an impressive win on Saturday night have exposed a potential weakness ahead of finals.    

The Dockers were picked apart at Optus Stadium, losing just their third game at home this season after the Swans turned the match on its head with a focus on controlling possession and taking uncontested marks.

John Longmire's team took 88 uncontested grabs to 30 in the second half and turned a 23-point deficit into an important 17-point win that gets them back in the top-four hunt.

Fremantle coach Justin Longmuir said his players were too slow to respond to the switch in style, but he was not concerned that clubs might bring a similar approach to the Swans in the final five rounds.  

"It's been something we've been pretty good at, and I don't think any team has been able to do that. We were just slow to adjust," he said. 

DOCKERS v SWANS Full match coverage and stats

"That was probably the most disappointing thing. As much as the players are communicating it to each other, we lacked energy in our defence. 

"If you lack energy in defence and you let a team control the ball like that, it makes it hard to get anything going on offence. It was the story of the second half.

"I didn't think we worked well together either. Usually we're a team that defends as a group, and we probably fought our own battles in defence a little bit too often."

Longmuir said a free kick against Jordan Clark on the stroke of half-time, making Lance Franklin's only goal of the game possible, was "not ideal" but shouldn't be seen as the difference in the match. 

He said captain Nat Fyfe, whose 15 disposals included only one kick, was "getting back to his best" at the coalface and brought teammates into the game with his hands.    

Key defender Griffin Logue was one of only a few winners in his position after holding Franklin to one goal and seven disposals, with key forward Rory Lobb needing assessment for a shoulder issue that he played through. 

Fremantle faces Richmond at Marvel Stadium next Friday night, with the fifth-placed Collingwood now level on 12 wins with the Dockers and Sydney just one game behind. 

Swans coach Longmire said the win was "terrific" and praised his players for driving the game style adjustment after half-time.

"It just took shape during the course of the game. You have to find different ways to play, but that is off the back of pressure and structure and effort," he said.

"It was off the back of strong defence. Make sure we maintain defensive work and then add to that. Our players adjusted well in the second half, so full credit to them."

Longmire said the Swans would not look ahead to a potential top-four finish after strengthening their position with back-to-back wins, with their ladder position "not relevant".

"We've been up and down a bit this year, in games and week to week. We need a bit of consistency," he said.