FREMANTLE'S backline was dealt the type of blow in round one that could easily have knocked it off course and prevented the subsequent form that has it positioned as the AFL's stingiest defence and a key reason behind the Dockers' 3-0 start. 

In less than 30 minutes either side of three-quarter time against Brisbane, the Dockers lost key defenders Brennan Cox and Oscar McDonald to serious injuries, and half-back Karl Worner to concussion after a brutal collision.

It was a rattling run of setbacks that brought the backline together in the days after to talk about how they were feeling about the early season blows and how they would move forward in 2024. 

The response has been emphatic. With captain Alex Pearce, Luke Ryan and Jordan Clark elevating themselves, and the rest of the backline delivering on their roles, the Dockers are ranked No.1 for fewest points conceded this season (60.0), fewest goals conceded from opposition entries (16 per cent) and contested possession and groundball differentials in defensive 50. 

Their biggest test comes against Carlton at Adelaide Oval on Saturday, with backline coach Matthew Boyd proud of the way the group has responded to the early setbacks and helped deliver an undefeated start for the Dockers.

"I feel like we've definitely rallied and come together, and it's been really mature in how we handled those losses to the backline," Boyd told AFL.com.au this week. 

"Backlines are pretty tightly knit, and whenever that sort of stuff happens I reckon it's just important to acknowledge how we're feeling about it. 

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"So that was the first thing we wanted to do as a group and not shy away from that, and once you do that and talk about it openly then you can just anchor and move forward from it. I think that's what we were able to do. 

"The players just saw it as a real opportunity that there was going to be some spots left open and if you're playing your role and contributing to the team in your role then you get a chance, and that's how the backline and the whole team really addressed some of those injury losses."

Pearce and Ryan have been in outstanding form in the opening three matches, with 20-year-old Academy product Josh Draper also emerging as a key defensive option since making his debut against North Melbourne and impressing with his composure against Adelaide. 

There have been unsung heroes, however, in a Dockers' backline that also adjusted to Hayden Young moving to the midfield and Heath Chapman missing the start of the season with a hamstring injury.

"Someone that has really stepped up from a leadership perspective is Jordan Clark. He's driving a lot of standards and he's quite vocal in our line meetings and team meetings and he's certainly very vocal on the field," Boyd said.

"Ethan Hughes plays a big role in that as well, being a really calm and stable member of the backline with his defensive work and his positioning. 

"Guys like that being able to step up and take a bit of that leadership burden off some of the older guys has been really important for allowing everyone to just be able to play their role. 

"When you've got a critical mass of players contributing to the leadership of a line or a team and you don't leave it up to too few, then I guess you've got more space in your mind and energy in your game to be able to perform your role."

Fremantle's backline and team defence was a major strength through 2022, with the team ranking No.2 for points conceded on the way to a breakthrough finals berth and come-from-behind elimination final win against the Western Bulldogs. 

Pearce and Cox were both represented in the top four of the best and fairest, while Cox was selected in the extended All-Australian squad in recognition of a high-functioning backline that didn't concede a single 100-point score in 24 games, and only one over 90 points. 

Last season was different, however, with the Dockers ranked No.11 for points conceded after giving up seven scores of 100 points or more.

Boyd knows the challenges will come for his backline, most notably against the undefeated Blues on Saturday, but there is confidence now that the group is well equipped to tackle what is thrown at it after some early setbacks.

"In the review of last season, it was mentioned by players that we weren't where we wanted to be as a backline … it was obvious that we didn't have the year that we wanted to," Boyd said. 

"So we wanted to make sure that we were doing everything right to be the best backline that we can possibly be. We want to be the most connected and competitive backline in the competition.

"They're a pretty proud group. Footy players are pretty proud guys and they're real competitors and they embrace the challenge. That's what they've done so far."