The Wallabies entered Saturday's match trailing both the All Blacks and South Africa in the standings but, with the Springboks in action later on Saturday, Michael Cheika's men moved into pole position with a 47-26 success, which marks New Zealand's joint-heaviest defeat and the most points they have conceded in a Test to Australia. "IT's direct, with force, so I've no option it will be a red card".
It could also put Barrett in doubt for New Zealand's World Cup opener against South Africa in Yokohama on September 21, another big blow after his fellow lock Brodie Retallick dislocated his shoulder in the 16-16 draw with the Springboks last week.
Winger Reece Hodge scored two of their six tries as Australia ran up their highest tally of points in 165 tests against the All Blacks and gave themselves a chance of regaining the Bledisloe Cup they last raised aloft in 2002.
New Zealand received a blow just before half-time of their clash with Australia when lock Scott Barrett was shown red for making contact with the head of Michael Hooper.
Hansen said there were issues that needed to be looked at ahead of the return leg of the Bledisloe Cup in Auckland next week.
"But once Scooter (Barrett) got red carded, you know, it's game over".More news: United States and China row over 'dangerous' Hong Kong reports on diplomat
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"It's a great atmosphere and great for the players to get the win but in the bigger scheme of things that's what we've got ourselves - a ticket to go there and take the opportunity that we're going to get given there".
Barrett's contact with Hopper at the breakdown was reviewed at length by referee Jerome Garces before the referee came to the decision that the lock's "shoulder and elbow on the neck" was "clearly risky, direct and with force". Our discipline was poor in the first half.
"It was dumb footy and we've got to be smarter than that. At the end, they found more space than we could cover".
"Mentally I would say they (his players) are pretty bruised", Hansen said before the squad left Perth on Sunday. Australia wanted to play footy, they wanted to play fast.
"If we can rectify some of those problems and turn up with an attitude that says we are hungrier, or as hungry as them, then we are in the game".