ANDREW Gaff's stunning brain fade has marred West Coast's thumping 58-point Western Derby victory over Fremantle, with the Eagles star's season in jeopardy after he floored Dockers young gun Andrew Brayshaw.

In what descended into the ugliest all-WA clash since the infamous Demolition Derby in 2000, the Eagles tightened their grip on a top-two spot but remarkably might also have seen their premiership hopes diminished by Gaff's unfathomable strike.

TEMPERS FLARE, EAGLES SOAR Full match coverage and stats 

With the game in West Coast's keeping during the third quarter, the usually placid Eagles onballer lashed out and dropped Brayshaw with a blow that sent the Dockers young gun to hospital with a fractured jaw and four displaced teeth. 

The strike will almost certainly be graded intentional and high impact, which would mean Gaff, one of the Brownlow Medal favourites, is sent straight to the Tribunal and looking at a minimum three weeks – the rest of the home and away season - on the sidelines. 

DEMOLITION DERBY 2.0 Five talking points

It was a shocking moment that ignited what had been a fizzer of a contest, with spot fires erupting everywhere during the second half.

Tension threatened to boil over between the arch-rivals, and veteran Fremantle defender Michael Johnson could also be facing a sanction from the Match Review Officer after he and Luke Ryan sandwiched Gaff during the final term. 

There were extraordinary scenes when Eagles coach Adam Simpson came to the interchange bench before three-quarter time to console a clearly distraught Gaff.  

"It's not my position to comment. All I know is Andrew is quite upset. He's really thinking about the Brayshaw family," Simpson said post-match.

"One thing I do know is Andrew's character, who he is as a person and a player can't be questioned.

"As much as it's going to look like it was intentional, I'm not quite sure it was.

"He was rattled (during the third quarter). He was in a bit of shock, I suppose. I was just trying to put my arm around him a little bit, because it was unfortunate and we've got to deal with it now."

Fremantle coach Ross Lyon was emotional after the game, and expected Brayshaw – last year's No.2 draft pick - would miss the rest of the season. 

"Andrew Brayshaw was king-hit 100m off the ball. He's got a fractured jaw and four displaced teeth that are caved in, and he'll be undergoing surgery tonight," Lyon said.  

"I think it's self-evident (what my thoughts are). I've got an 18-year-old kid that I saw in a real mess when I came down to the rooms and his mum in tears as I was walking in. It's not very palatable."

WATCH Gaff's hit sparks Derby chaos

While the fallout from the incident will dominate headlines, West Coast smashed the Dockers 21.16 (142) to 13.6 (84) to move six points clear of third-placed Greater Western Sydney and two wins clear of Melbourne in fourth spot.    

It was the Eagles' seventh-straight victory over the Dockers, and extended their overall Derby record to 28-20.

Fremantle remains in 13th spot on the ladder, but is still searching for its eighth win for the year to match last year's tally.

West Coast's small forwards combined superbly with Jack Darling on Sunday to lead the victory in the absence of gun spearhead Josh Kennedy.

Darling overcame some early wobbles in front of goal to snag four majors, while Jamie Cripps (four) continued his excellent form and Liam Ryan (three) made the most of his return after a club-imposed ban.

With needing to mind injured Freo superstar Nat Fyfe, West Coast gun Elliot Yeo was unleashed in midfield and produced a stellar 26-disposal, two-goal performance to claim the inaugural Glendinning-Allan Medal as best afield.  

Jack Redden backed up his excellent effort in the round six Derby with an equal game-high 33 touches and a goal – matched by Gaff - while 150-gamer Brad Sheppard was also superb in defence with 26 touches.  

Experienced Freo duo David Mundy (27 disposals, eight clearances) and Lachie Neale (26, nine) needed big games if the Dockers were going to be any hope of upsetting the high-flying Eagles. 

But even their best efforts and Bradley Hill's (30 disposals) spike in form wasn't nearly enough.

West Coast's forward line was vastly more damaging, with 37 scoring shots from 60 inside 50s compared to 19 from 49 for Freo.

In a positive for the men in purple, returning spearhead Matt Taberner shook off some early rust to finish with two goals for the Dockers, while Michael Walters took a Woolworths Mark of the Year contender and finished with a couple of majors.  

Before copping Gaff's blow, Brayshaw looked to be on the way to a long-awaited NAB AFL Rising Star nomination with 16 disposals.

Lyon would have been tearing his hair out at some horrible skill errors before the long break, which cost the Dockers any momentum as they trailed by 33 points. 

In the end, the Eagles had too many answers, but tougher challenges await with Gaff set to join Nic Naitanui and Kennedy on the sidelines and veteran defender Will Schofield also suffering a hamstring injury.

MEDICAL ROOM
West Coast: Jeremy McGovern came to the bench and appeared to have his pulse checked but returned shortly after. Fellow tall defender Will Schofield came off almost immediately following McGovern's scare and was done for the day with a left hamstring injury.

Fremantle: Brady Grey came off with the blood rule after a heavy hit early in the second term but wasn't off for long. Andrew Brayshaw copped a high blow from Andrew Gaff and was bleeding profusely from the mouth early in the third term as he came from the ground and was taken to hospital with a suspected broken jaw. Brandon Matera copped a heavy hit straight afterwards from Nathan Vardy and had to go the rooms with his right shoulder hanging low.

NEXT UP
The Eagles head to happy hunting ground Adelaide Oval to face Port Adelaide but, despite a 5-0 record against the Power at the venue, will have their work cut out against the desperate Power. Fremantle hosts bottom-placed Carlton in a golden opportunity to claim an eighth victory, equaling last year's tally.

WEST COAST     4.4     9.7     16.10     21.16     (142)                  
FREMANTLE      1.2     4.4        8.6        13.6        (84)            

GOALS

West Coast: Darling 4, Cripps 4, Ryan 3, Rioli 2, Yeo 2, Lycett 2, Vardy 2, Redden, Gaff
Fremantle: Matera 2, Taberner 2, McCarthy 2, Walters 2, Cox, Ballantyne, Langdon, Darcy, Neale

BEST 
West Coast: Yeo, Redden, Sheppard, Lycett, Cripps, Ryan
Fremantle: Mundy, Neale, Walters, B.Hill, S.Hill

INJURIES 

West Coast: Schofield (left hamstring)
Fremantle: Brayshaw (jaw) 

Reports: Nil

Umpires: Stephens, Williamson, Ryan 

Official crowd: 57,375