NO EAGLE took the 2015 Grand Final disaster harder than Elliot Yeo.

But one of the few silver linings to that 46-point defeat against Hawthorn was that from the wreckage West Coast gained a ruthless competitor who vowed never again to feel the despair of underperforming when it matters most. 

"I'm not shy to say that it was probably one of my worst performances as a footballer and to play one of your worst games of your career, you don’t really want it on the big stage, and for me that was pretty heartbreaking," a candid Yeo told AFL.com.au. 

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Yeo had only turned 22 two days before the 2015 decider, and was far from the only Eagle below their best.

But picking up just five touches – only Eagles ruckmen Nic Naitanui and Callum Sinclair had fewer – has stayed with him and fueled his rise as a star of the competition.

"I took that as motivation going forward and thought you can't get any worse than that, so that helped me build as a footballer," Yeo said.

Elliot Yeo and Mark Hutchings after the 2015 Grand Final. Picture: AFL Photos

After an up-and-down 2016, Yeo was settled across half-back last year and earned his first All Australian jacket.

But with the Eagles midfield desperately in need of some X-factor, pace and power, the former Lion has this year morphed into an A-grade onballer, averaging 25 disposals and booting 13 goals. 

Yeo enters this season's decider against Collingwood as one of Adam Simpson's key match-winners, and while the Hawks nightmare feels like "forever" ago, he hasn't forgotten the harsh lessons and mistakes made.

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"It was spoken about a fair bit at the start of 2016 and if we do get there what would unfold and how would we go about it differently," Yeo said.

"Just handling it and taking it as it comes and trying not to play the game before you've already played it.

"I'm just staying relaxed and focused."

There is a sense of calmness about the Eagles – 12 of whom will return to the Grand Final stage.

Part of that is Simpson's influence, but West Coast boasts a mature core group which is on a mission after falling short in the past three September campaigns.

"We've got one game to go, and one job to do and four quarters to play," Yeo said.

"It's probably a little bit different to 2015 when we were probably thinking 'what's going on here?' and riding the wave.

"It feels like we've got a job to do but I'm sure Collingwood will be thinking the same thing as well."

The Eagles have beaten the Pies twice this season, including a 35-point confidence-booster at the MCG in round 17, but Nathan Buckley's men could be peaking at the right time after dismantling Richmond in a preliminary final stunner. 

"To be able to beat Richmond at the 'G, and especially with the form Richmond have had, it's phenomenal," Yeo said.

"We're pretty confident that our game plan and style of play will hold up pretty well. But Collingwood are a really good team and their pressure around the football was second to none against Richmond.

"They'll be bringing that and their intensity as well, so it's going to be game on and I'm looking forward to it."