West Coast coach Adam Simpson says the Eagles must improve in six days if they expect to beat Fremantle despite the team's 33- point win over St Kilda at Etihad Stadium yesterday.
West Coast jumped above Adelaide into 10th place after winning 15.13 (103) to 10.10 (70).
However, they remain two games behind eighth-placed Gold Coast, who beat Geelong on Saturday.
The Saints triumph was West Coast's second win in a row, after beating the Suns in Perth last week. But Simpson said their form was still below what was required to beat Fremantle.
"We've got to play better than we did tonight," Simpson said.
"Contested ball for us was good. Our midfield - we've been a bit short on numbers in recent weeks with some injuries so we think we're still growing in that area.
"Our ball use needs to improve and we're hoping that'll help our team defence as well.
"They're in better form than they were the first time we played them. We've had another four or five games.
"It hasn't been too long since we played them. We're better for the experience.
"I'm better for the experience. But I don't think it makes it any easier."
Fremantle are in superb form and launched into the top four after demoralising Brisbane on Saturday night.
The Dockers allowed Brisbane just 17 inside 50s and Simpson said West Coast would need to kick the ball to their forwards better against Fremantle than they did yesterday. The Eagles had 52 attacking 50m entries against St Kilda, but often bombed the ball in, allowing the Saints to spoil and rebound.
"We're working really hard on our ball use and sometimes I thought today it fuelled opposition rebound," Simpson said.
"We turned the ball over and quite often without any pressure and they kicked seven goals from our forward half - rebounds or kick-ins. That fuelled their supply. If we can fix that we can probably help our defence."
Fremantle beat West Coast by 19 points in round seven when the Eagles were without Mark LeCras, Sharrod Wellingham and Xavier Ellis. Jeremy McGovern has also come into the team and had an immediate impact in the forward line.
He kicked three goals yesterday, giving him eight in the past three matches.
"We felt he was looking really dangerous," Simpson said.
"So, if JK is having an off night and we can kick the ball to him, we're confident he can win his one-on-ones."
West Coast haven't beaten Fremantle since 2012, but will be strengthened by the return of All-Australian ruckman Dean Cox, who was given an extra week of rest to prepare for the derby.
Simpson was confident Luke Shuey would be cleared by the match review panel over a clumsy spoil which took out the legs of St Kilda captain Nick Riewoldt.