ALL SEASON we've wondered when, or if, ruthless West Coast would emerge. 

On Saturday night, with their arch-rivals in the sights, the Eagles truly found their killer instinct, belting Fremantle and moving ominously into outright second spot on the ladder.

The 91-point thumping, inspired by fit-again star ruckman Nic Naitanui, first-time Glendinning-Allan medallist Brad Sheppard and a fleet of dangerous small forwards, in slippery conditions was a clear warning that the reigning premiers are finding their groove when it counts.

Ed Langdon gets a handpass away under Chris Masten pressure. Picture: AFL Photos

But for the shockingly wayward Dockers, the 19.8 (122) to 2.19 (31) defeat leaves them in a spiral at 7-8 after three-straight losses and with their finals ambitions in serious peril.

Heading into the contest, all the talk was about West Coast equalling the record nine-game winning streak in derbies, but that wasn't the only historical mark the Eagles hit.

GAMEBREAKER Vintage Nic Nat destroys the Dockers

In improving their head-to-head tally to 30-20, the Eagles registered the second-biggest winning margin between the WA clubs and held Freo to the lowest-ever score, worse than the Dockers' 5.6 (36) effort in Ross Lyon's first derby in charge in 2012.

Unfortunately for the 56,358 fans who braved the weather, the build-up to the 50th Western Derby packed more punch than the match.

EAGLES MAKE HISTORY Full match coverage and stats

While it was a throwback to a seemingly bygone era, Nic Naitanui and returning big man Aaron Sandilands contested the opening bounce, the contest quickly fizzled out as West Coast assumed total control after an intense opening 10 minutes.

One team was playing dry-weather football and moving the ball with precision, while the other was slipping and fumbling and unable to find a way forward.

West Coast's well-oiled machine had the Dockers on the ropes at quarter-time, leading by only nine points but with Ross Lyon's men hanging on for the bell after being beaten up around clearances (12-7) and the contest (41-34).

In the second stanza, the Eagles landed the killer blow.

NO PANIC STATIONS Ross Lyon keeping calm in midst of form slump

With Naitanui leaping all over Sandilands at the centre bounces, West Coast kicked four of eight goals directly from restarts.

Alarm bells were ringing when third-gamer Jarrod Cameron snapped his first inside a minute after a wondrous one-handed pick-up by Naitanui, before converting from a free-kick for a dangerous tackle.

After ruckman Tom Hickey snapped truly from his left foot Dockers fans would have known this probably wasn't going to be their night as the margin ballooned to 25 points.

When Ethan Hughes stepped over the boundary line deliberately and Cameron snapped his third goal – from his third kick – for the quarter, they definitely would have.

Remarkably, without ill spearhead Josh Kennedy (who was a late withdrawal), the Eagles had 10 scoring shots from 13 inside 50s, while Freo managed just five behinds from 16 entries.

Too often, the Dockers were beaten by what they know, bombing the ball for West Coast's defence to intercept or spoil, with returning talls Jeremy McGovern and Tom Barrass impassable.

On a dirty night, it took until the 26-minute mark of the third quarter for Michael Walters to steer through their second goal, breaking a run of 12-unanswered for the Eagles after the margin had blown out to 72 points.

NIC NAT'S BACK Adam Simpson praises star ruckman's performance in win

The Eagles had winners everywhere, with prolific onballer Andrew Gaff (34 disposals) doing as he pleased despite persistent boos from Freo fans, with sidekick Luke Shuey (28, nine clearances), and backmen Sheppard (25) and Shannon Hurn (22) a cut above.

Cameron finished with four majors, running riot alongside Jamie Cripps (four) and Jack Darling, who backed up his five-goal bag against Hawthorn with another four.

West Coast, which showed signs it was shaking off rust in the past two home wins against the Western Bulldogs and Essendon, received a valuable 7.9 percentage boost as Adam Simpson's men moved into the top-two for the first time this season.

But the Dockers have some serious soul-searching to do after going down to Melbourne, Carlton and now the Eagles.

Darcy Tucker (29 disposals) could hold his head high, usual suspects Michael Walters (23), Nat Fyfe (21) and David Mundy (18) never stopped trying, but once again too much was left to too few. 

MEDICAL ROOM
Fremantle: Fyfe came off early in the second term and had his right arm checked out by the doctor and physio close to the interchange bench but played out the game. Travis Colyer also appeared to pick up a corked thigh in the final quarter.

West Coast: Young backman Liam Duggan came off twice in the opening term, first with an ankle or shin issue, before heading to the rooms with a cut to his head.

NEXT UP
The Dockers travel to Launceston, where they have a 1-10 record, to face the Hawks, who they have lost 11 of the past 12 encounters against. Meanwhile, the Eagles host the stuttering Magpies, who they have beaten four straight times, on Friday night at Optus Stadium.

FREMANTLE    1.2       1.7       2.14     2.19 (31)
WEST COAST  2.5       10.7     14.7     19.8 (122)

GOALS
Fremantle: McCarthy, Walters,
West Coast: Cameron 4, Cripps 4, Darling 4, Hickey 2, Rioli, Masten, Shuey, Ah Chee, Yeo

BEST
Fremantle: Tucker, Walters, Fyfe, Hamling, Mundy
West Coast: Sheppard, Gaff, Naitanui, Shuey, Hurn, Cripps

INJURIES
Fremantle: Colyer (corked thigh)
West Coast: Josh Kennedy (illness) replaced in selected side by Brendon Ah Chee

Reports: Nil

Umpires: Fisher, Williamson, Mollison

Official crowd: 56,358 at Optus Stadium