David Pocock moves from blindside flanker to No8 to make way for Lukhan Tui at No6. As expected Nick Phipps is in at scrum-half for Will Genia, who suffered a fractured arm in game two.
Cheika left nobody in any doubt that his side was just as fired up for tomorrow as the Irish camp having come up short in Melbourne.
“I think there’s a very clear focus. We’re coming in off the back of a loss, a close one albeit, but still a very sharp focus on things that we can immediately improve,” said Australia’s head coach.
“There’s a couple of things that we can amend and improve to get us in front when it’s a tight call... but they’re big games and we want to get experience in putting ourselves in the position where we’ve got to play for these trophies and have these types of weeks where everything’s on the line.
“Enjoy them and really be clear on how we can get the results in this situation.”
Genia’s injury and Phipps’ promotion to the No9 jersey in a backline also featuring his Waratahs teammates Bernard Foley at fly-half, Kurtley Beale at inside centre, and Israel Folau at full-back, means a first opportunity of the series off the bench for Brumbies scrum-half Joe Powell.
Another Waratahs player, back-row Ned Hanigan, also features for the first time as a replacement on a bench which remains with a split of six forwards and two backs. It means no place in the squad for Caleb Timu, who started the first two Tests at No8.
“Ned has rehabbed himself really well, he played 12 Tests last year so he’s got good experience,” said Cheika.
“Having Lukhan (Tui) in the starting side, it gives us a bit more flexibility as opposed to having Caleb and Pete (Samu) who are back-row only, it allows us to play a bit more with that, he’s more set-piece, Pete would be a bit more roaming.
“It’s going to be a very physical battle, the third in a row, and I think the forward pack will need that type of reinforcement coming on to make sure we finish strong.”