FREMANTLE'S showdown with Port Adelaide is crucial for any September success if you listen to Freo coach Ross Lyon.

While Fremantle moved back into fourth spot with a 58-point win over the Brisbane Lions on Sunday, it will need to beat Ken Hinkley's Power at Patersons Stadium next Saturday to retain its position and the finals double chance.

Since the top-eight system changed to its current finals format in 2000 no team has won the premiership from fifth or lower.

When asked the value of finishing in the top four, the Freo boss was succinct.

"No-one's won it from fifth, but a few have won it with the double chance," Lyon said.

"The reality is it's sudden death for top four next week. We're really thrilled by that. We're excited by the challenge, we accept the challenge, as Port do.

"They're going to ask some questions of us and we're going to ask some serious questions of them, so it's really game on from here.

"You don't sneak your way into the top four, you've got to win your way and we're excited by that."

Fremantle blew the Lions away in the first half despite losing skipper Matthew Pavlich in the warm up with a tight quad.

Lyon didn't seem too concerned by the injury and said his captain would be assessed through the week.

He was however worried by the third quarter, where the Lions kicked two goals to one to stifle Freo’s momentum.

"I thought we stuffed the third quarter up," he said.

"Our over-use. We were winning the ball and got a bit cute, turned it over and they scored.

"It was a really valuable lesson [on] how quickly it can change. Too much handball, not enough kick."

One thing that pleased him was the reunion of small forwards Hayden Ballantyne and Michael Walters, who kicked three goals apiece and caused the Lions' defence headaches all day.

He expected both to be better – individually and in tandem – against the Power.

"Sonny (Walters) will only get better," he said.

"I think you'll see him play better next week to be truthful. ‘Ballas’, I thought he was really good. He always struggles after one week off, so he should be better again."