Fremantle is storming towards a historic AFL campaign.

Never has the club won more than 17 games during a regular season, and never has it finished a season with a higher percentage than it currently boasts.

Even in 2015, when Fremantle won those 17 games, drew one and finished top of the ladder, Ross Lyon's charges only had a percentage of 118.

This season, Justin Longmuir's side sits on 142 per cent with five games to play.

In tonight's Western Derby against West Coast, the Dockers could match their best-ever return and set up a comfortable run into finals.

A victory would see them remain at least three games clear at the top of the ladder with four matches to play, meaning they would need to win just one of their remaining games to clinch top spot.

It's an enviable position, but after a barnstorming run of 14 wins in a row, recent weeks have shown sides are starting to get a handle on the Dockers.

Fremantle has lost four of its past five first halves, though it has gone on to win all bar one of those matches.

It's something Longmuir is acutely aware needs monitoring, but otherwise there's little reason to panic.

His side boasts the stingiest defence in the league while also being the third-highest scoring.

The three-headed dragon of Jye Amiss, Josh Treacy and Patrick Voss has kicked 120 goals up forward.

The midfield is humming with or without Hayden Young, who has become something of the cream on a pretty spectacular cake.

The premiership window isn't just open for Fremantle. It's been blown off its hinges.

Eagles on the up

West Coast shouldn't, on paper at least, pose much of a problem for the Dockers.

The Eagles have won just four games this year, and not since defeating a hapless Essendon back in May.

But that doesn't tell the whole story of coach Andrew McQualter's side.

In round eight, the Eagles returned from Melbourne after a 101-point belting by St Kilda.

In the three weeks prior, West Coast had been thrashed by Sydney, Geelong and the Dockers.

Things looked bleak for the long-suffering Eagles faithful who had entered the season hopeful their club's rebuild would start bearing fruit.

Indeed, the flowers are starting to bloom, and it seems the fruit isn't too far away.

West Coast may have only won two more games since that shellacking by the Saints, but it has been a lot more competitive.

In their opening eight rounds, the Eagles' average margin was minus 46 points, which included wins in rounds two and three.

Since then, that margin is just minus 11 points. They beat GWS and Essendon, lost to Port Adelaide by a goal and North Melbourne by a point.

They led at half-time against the Western Bulldogs and Brisbane.

Harley Reid has not dropped below 20 disposals since that loss to Saint Kilda in a sign he's finding consistency in his game, while Jake Waterman has kicked three or more goals in eight of his past 11 games.

McQualter has stated his side is hunting a "scalp" to crystallise its improvement. Fremantle would be the ideal trophy.

At Perth Stadium tonight, both the Dockers and Eagles have something to gain, but only one has a lot to lose.