Reaching the final four, the Brumbies were Australia's top Super Rugby Pacific side and boasted the best set piece which Rennie sees as the key to ending a run of eight successive losses to Eddie Jones-coached England teams.
With Brumbies mentor Dan McKellar now full-time Wallabies forwards coach and putting his stamp on the side, there's seven in the starting side with five on the bench.
"The line-out and maul is a massive part of the game now and you don't have a genuine threat up front it's pretty easy to defend beyond," Rennie said on Thursday.
"If you've got a good maul teams have to spend a bit of time working out how they're going to defend that and they're going to have to use some bodies to do it which creates opportunities elsewhere.
"It's an area that we feel if we can overshadow England then it gives us an opportunity to get our game going and put a bit of heat on the right end of the field.
"The Brumbies were clearly our best performing side, but we're picking individuals and we're really happy with the group."
Among the selections were two debutants, with Brumbies lock Cadeyrn Neville and Waratahs hooker Dave Porecki named for the Optus Stadium showdown.
Aged 33, Neville is the third oldest debutant since WWII with his selection coming 10 years after he was first included in a Wallabies training squad.
Porecki, 29, also took the long way around, spending five years playing in the UK before returning to Australia in 2020.
"They've got a genuine hunger and a thirst," Rennie said of the duo.
"I look at 'Nev', 33 years old, but if you've seen him training he's a really good athlete.
"He's a big man at 125 kilos so very important to us from a set piece point of view as he's very good at maul, line-out, scrum and from a perseverance point of view it's a great story."
Quade Cooper will wear the Wallabies No.10 jersey with youngster Noah Lolesio on the bench with Rennie saying James O'Connor "lacked sharpness" after a run of injuries.
"James missed a big chunk and didn't play too many Kiwi games and had two different injuries and whilst he's back and fit and available he just lacks sharpness around the skill set," Rennie said.
"Noah's played very well and we have a lot of confidence and he's trained very well, and Quade brings a calmness and he has massive experience and has trained very well."
Burly prop Taniela Tupou (calf) is now targeting the second Test in Brisbane, leaving utility back Jordan Petaia on the bench as the sole Queensland player in the squad after their disappointing end to the season.
Reds halfback Tate McDermott also paid the price with Waratahs No.9 Jake Gordon preferred, while Queensland No.8 Harry Wilson was also shaded for selection.
The back row sees Brumbies big man Rob Valetini at No.8 and Rebel Rob Leota at blindside flanker, alongside skipper Michael Hooper.
Samu Kerevi will partner Brumbies centre Len Ikitau while fellow Japan-based Marika Koroibete and Melbourne's Andrew Kellaway will start on the wings.
Wallabies: Tom Banks, Andrew Kellaway, Len Ikitau, Samu Kerevi, Marika Koroibete, Quade Cooper, Nic White, Rob Valetini, Michael Hooper (c), Rob Leota, Cadeyrn Neville, Darcy Swain, Allan Alaalatoa, David Porecki, Angus Bell. Res: Folau Fainga'a, Scott Sio, James Slipper, Matt Philip, Pete Samu, Jake Gordon, Noah Lolesio, Jordan Petaia.
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