The hosts enter as favourites yet few could write off their French counterparts as a pair of last-gasp finishes in the opening two Tests sets the scene for an unpredictable ending.

Swain will partner Lukhan Salakaia-Loto in the second-row as the Wallabies hunt for a series victory against France at Brisbane's Lang Park on Saturday night.

The towering 24-year-old's first start coincides with those of livewire scrumhalf Tate McDermott and outside centre Len Ikitau, the former schoolboy teammate who has mirrored his rise through the ranks.

"That's probably one of the most special things about it, the connection Len and I have. He's one of my best mates, if not my best mate," Swain said of his ACT Brumbies teammate.

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"It's just good to have that. Obviously going to [Brisbane Boys' College] together, playing rep footy together in Brisbane, Tuggeranong, Canberra Vikings, we've sort of done it all together.

"It's pretty special, I love that bond I have with Lenny."

Ikitau's move into the starting XV shifts Hunter Paisami to inside centre and veteran Matt To'omua to the bench.

But Swain concedes the addition of a fleet-footed pairing of Ikitau and McDermott will count for little unless the Wallabies can dominate the breakdown.

Wallabies coach Dave Rennie has already urged referee Ben O'Keeffe to scrutinise France's breakdown tactics closely in the decider.

Now Swain wants to set the tone. As he begins to rattle off what he needs to do to "nail his role", among the tasks at hand is getting up in a lineout and ensuring the Wallabies win quality ball.

Then there is his determination to be "physical around the park, and driving stuff like the attacking breakdown, being physical, trying to slow their ball down when they're attacking at us".

These are the traits Rennie wanted to see from Swain before he called him into a Wallabies camp.

They're the hallmarks of Swain's game the young Brumby worked tirelessly upon under the tutelage of Laurie Fisher and Dan McKellar outside of training in Canberra.

Now they loom as key components of the game plan for a Wallabies side chasing silverware.

"We've got to give Tate and all of our backs a good platform to play off," Swain said.

"We can't have their captain, their No. 8, their 12, all those blokes that were pests on the ball in Tests one and two, we can't have them slowing down the ball so we can't play.

"Expect us to be direct and more brutal at the breakdown.

"It just goes back to our mindset. It's a bit of a shorter turnaround, especially these past two Tests, we haven't really had much time to get body on body considering there's a few sore bodies getting around.

"It's also just ticking the box upstairs and making sure you're ready to absolutely flog a breakdown if you have to.

"We just need to boost our physicality tight around the ruck. They've had a bit of dominance there, especially tight around the ruck. We just need to improve that individual contact.

"It's just more our mindset around our attacking breakdown and just winning the race to the breakdown. Once blokes flick the switch there, we won't have much of a problem."

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