ALL SUMMER long we were told Fremantle had changed.

A team that skipper Nat Fyfe admitted lacked an identifiable brand, was criticised for playing without flair and had ranked 16th for scoring last season, promised us an attacking overhaul.

Twin targets Jesse Hogan and Rory Lobb were signed, sealed and delivered after the Dockers went all-in at the trade table, and playing with penetration would be the signature style of a simplified gameplan.  

With the most glaring weakness since 700-goal legend Matthew Pavlich's decline and retirement addressed, expectations of a finals push were wholeheartedly embraced.  

The rebuild, it seemed, was almost over.

But nobody saw Sunday's 82-point dismantling of North Melbourne coming, especially after the bombshell news dropped that Hogan was battling anxiety and wouldn't be available. 

DOCKERS GO LARGE Full match coverage and stats

Just a week out from his blockbuster unveiling, the Dockers revealed their marquee man had been drinking heavily and had turned up to training in an unfit state.

With a number of key players already sidelined by injury and amid concerns about a thin midfield in the wake of Lachie Neale's departure, it was the last thing Fremantle needed.  

What Fyfe labelled a "juicy" start to the season against the Roos, Suns and Saints suddenly looked like a potential banana peel that could heap pressure on an under-siege club.  

Nat Fyfe fires up his teammates before the opening bounce. Picture: AFL Photos

But fans need not have worried, and ironically it was a former prized recruit who emerged from the shadows and led the thumping victory at Optus Stadium.

Unable to even earn a spot in the Dockers' 26-man squads for their two JLT Community Series losses, out-of-favour forward Cam McCarthy was called up and seized his opportunities.  

GAMEBREAKER Super Cam's big bag

It didn't start well when McCarthy's first shot skewed off the side of his left boot and went out of bounds.

But the former Giant was away after he snuck in front of Robbie Tarrant to pluck a mark, went back and squeezed in his first major from 50m directly in front. 

It sparked an equal career-best five-goal haul from 20 disposals, just reward after he kept his chin up when he was out of the side.

'HE LOOKED IMMACULATE' Ross full of praise for Cam

"I played a fair bit of footy with him at the Giants and him playing as that third tall (forward), he's a really good hit-up player and he's got good skills," Dockers debutant Rory Lobb told AFL.com.au. 

"He's been one of the hardest workers all pre-season.

"He was unlucky to miss out in the JLTs, but him coming in and playing his role was unreal."

The Roos, without veteran backman Scott Thompson (suspension) and Majak Daw (hips), lost youngster Ed Vickers-Willis to a suspected ACL rupture in the first term and leaked like a sieve defensively. 

But credit must go to Fremantle's injury-hit midfield, which helped supply 68 inside 50s to a ravenous attack that threatened in the air and swarmed at ground level.

Twelve Dockers hit the scoreboard, with Lobb and debutant Lachie Schultz both coming to the party with two majors each after half-time. 

Fremantle's 21.15 (141) was the club's highest score since round 12, 2016 when it smashed the struggling Brisbane Lions by 83 points at the Gabba.  

It was also the Dockers' biggest win over the Kangaroos, and coach Ross Lyon could take plenty of satisfaction from seeing North's backline crumble under immense pressure.

"(It’s) well-documented we got the gameplan out early, we modified, we wanted to be more penetrative with the ball and we knew our stoppage work and defensive mechanisms could be strong if we did that," Lyon said post-match.

"We felt through the JLT, although that can be a little bit deceptive, our best was very good and I think it was fortunate to play the two reigning Grand finalists.

"The players always have to bring great effort and execute, and I thought they did that really well today."

WATCH Ross Lyon's full post-match media conference

After a tumultuous week, it was said Fremantle's season-opener was the club's most important game since the 2015 preliminary final.

The Dockers couldn't have responded better, and when the "Freo" chant reverberated around Optus Stadium just before three-quarter time the atmosphere was forbidding for visiting players and fans, reminiscent of the club's most successful era under Lyon.

How much Fremantle has improved won't be known until a tough stretch of games starting with the round four Western Derby.

But there is optimism that the Dockers have changed, and for the better.