DENYING Collingwood giant Mason Cox the chance to launch at the ball will be West Coast full-back Tom Barrass' priority in the Grand Final after watching the "fantastic" American Pie dominate Richmond.

The Tigers were clueless against the 211cm forward, who used body work off the ball and his enormous reach to terrorise star defenders Alex Rance and David Astbury.

Cox hauled in eight contested marks and booted three goals as the Pies orchestrated a famous preliminary final upset.

"He's a big man, he's 6'10 and his arms are two-and-a-half metres long each. When he's got a run and jump at it he's pretty hard to stop, so it will be about that," Barrass told AFL.com.au.

"He played a fantastic game on Friday night.

"I think consistency is something you take a little while to find early on in your footy career and it's something probably that I'm still trying to find a little bit as well, so I think it was good to him to silence a few critics that were getting into him.

"He's a great contested mark and he's going to be a great player, so it will be a great challenge."

However, Barrass will be ready for the big Texan, and got the job done when the Grand Final combatants met in a pulsating qualifying final.

He held Cox to just four kicks, two marks and no score, unsettling the Pies' main marking target with cleverly-timed bumps.

The strength of the Eagles' defence is their ability to read the play, and star Jeremy McGovern, veteran Will Schofield and skipper Shannon Hurn will be called upon to assist Barrass.

"I think we do that well as a side, we come over and support and help when we need to, and it's great having Gov and Schoey there in particular to come over and help support you when you are tied up," he said.

Few key forwards have worried West Coast's defence this season, and barely at all since the first half of the campaign.

The Eagles were all at sea in round one when Sydney superstar Lance Franklin was the show-stopper with eight goals, while Carlton youngster Harry McKay slotted four at the MCG in round five.

Apart from that, Tigers star Jack Riewoldt (five, round nine) is the only other genuine tall to kick more than three goals in a game, although Tom Hawkins (3.3, round three) and Taylor Walker (3.4, round 15) were inaccurate.

It has generally been nimbler types who have done the damage, such as Saint Tim Membrey (six goals, round 11), Pies young gun Jordan De Goey (four, round 17) and Demons hard nut Jake Melksham (four, round 22).

No single opponent has kicked more than two goals against the Eagles this finals series, and they muzzled the AFL's highest-scoring team in the preliminary final, fueling belief in their defensive system.

"We're very much a very connected backline and it's settled there a little bit," Barrass said.

"On top of that we're all very good mates, there's a lot of trust there. We trust each other to get the job done and play our role.

"You don't need to be outstanding – although Gov tries to trump us a fair bit of the time."

Barrass is feeling excited and nervous before his Grand Final debut, and learnt from watching on during West Coast's 2015 disaster against Hawthorn the importance of being predictable to your teammates.

"I can still remember particular things we took out of the review of that game, even little things like that you carry through with you," he said.

"The big moments of games like that and the immense pressure that happens forces people to try to do things outside of their role and what they've been doing all year.

"It's just about playing a real team game and playing your role."

Twelve Eagles will step back onto the big stage eager to make amends, while Barrass hopes to fulfill his childhood dream.

"I think you've been dreaming since five years old of being a premiership player," he said.

"That's the goal and I think you've got to embrace the dreaming a little bit without letting it distract you from the task at hand.

"You see your teammates, your brothers who care so much about it to go down convincingly in a Grand Final like that, it does hurt.

"A few boys will still have it in the back of their mind."