Some of the All Blacks' biggest names are copping rare heat ahead of the Bledisloe Cup decider at Eden Park, none more so than legendary five-eighth Dan Carter.

Rarely have so many All Blacks played below their best in a big Test as they did in Saturday's 27-19 loss to the Wallabies in the opening Bledisloe encounter in Sydney. Their knowledgeable rugby public are getting nervous, not so much about possibly conceding trans-Tasman supremacy for the first time since 2002 but more about the implications for the Rugby World Cup title defence starting next month.

In the backline alone, Carter, half-back Aaron Smith, centre Sonny Bill Williams and winger Julian Savea all had poor games at ANZ Stadium while veteran Conrad Smith was quiet. In the pack only hooker Dane Coles appears to be at the top of his game, and the sight of champion backrowers Richie McCaw, Kieran Read and Jerome Kaino being bested - along with the scrum - did nothing for Kiwi confidence.

History suggests the All Blacks will turn it around with a big win on Saturday as nothing sharpens them like a setback - recall the 51-20 shellacking they handed the Wallabies at Eden Park last year after being held to a draw in Sydney. But there is more at stake this time with the World Cup ahead.

And no one will be under as much scrutiny as Carter.

His halves partner Smith's brain snaps indirectly contributed to two Wallabies tries but that was a one-off night in an outstanding season. Carter has yet to show in 2015 that he can reproduce the form needed to steer the world champions successfully at his fourth World Cup and time has all but run out.

Kiwi fans' comments online have been awash with Carter concern, fans worried that coach Steve Hansen has used him for limited returns in three of four Tests when he could have given more time to Lima Sopoaga, who debuted promisingly in the win over the Springboks in Johannesburg.

The 33-year-old Carter's once-deadly running game was again MIA last weekend, as were his famous rugby smarts as he became all too predictable. He failed to chip kick in behind the rushing Wallabies defence swamping his backline and his kicking game seemed down on confidence with several errors.

Having shown such faith in his ageing great, Hansen seems unlikely to change at this late stage and rule Carter out of a farewell home Test. It won't just be the Wallabies under the pump at Eden Park.