The Wallabies will be better prepared to counter Ireland’s influential five-eighth Johnny Sexton in Saturday’s deciding Test in Sydney, but have their own issues to address according to attack coach Stephen Larkham.

Sexton, who came off the bench in the first Test loss in Brisbane, controlled the game superbly behind a dominant pack in Saturday’s second Test win in Melbourne.

“I thought Johnny Sexton controlled the game really well,” said former Wallabies five-eighth Larkham.

“But good for our guys now to have seen that and getting an understanding of how he controls the game and it will allow us to be better prepared for this week.”

For all of Ireland’s strong play in Melbourne, Larkham felt Australia’s woes were primarily self inflicted.

“I think it was more down to us, it was the inaccuracy in our kicking game and it was our poor discipline in our defence,” he said.

“We spoke about it before the series started. Ireland are very good on capitalising on opposition teams who are penalised a lot and that was us on the weekend.”

Australia will be forced into at least one change for the Sydney Test, with halfback Will Genia ruled out with a fractured arm.

His experienced deputy Nick Phipps is expected to start in his place.

The Wallabies are hopeful lock Adam Coleman will be ready for the decider after copping a head knock in Melbourne.

Coleman posted a photo on his Instagram account showing the swelling on his cheek had reduced substantially since Saturday.

He is expected to undergo HIA protocols during the week to establish whether he’s fit to play.