All Blacks coach Scott Robertson admitted his delight at winning the Bledisloe Cup for the first time in his career was tempered by a realisation his team remain a work in progress after their narrow win over Australia in Sydney on Saturday.

The All Blacks led 21-0 after 15 minutes but faltered badly in the second half, only just holding on with 13 men at one point to beat Australia 31-28 in the first Bledisloe Cup test.

New Zealand scored four tries in the first 25 minutes and held off a second-half Australia fightback with 13 men to beat the Wallabies 31-28 in a Rugby Championship thriller.

Practically giftwrapping the Bledisloe Cup for the All Blacks, the Wallabies looked set for yet another blowout loss, until it didn't.

The Bledisloe Cup series between Australia and New Zealand comes around each year as a high point of the Southern Hemisphere rugby season.

All Blacks coach Scott Robertson admitted his delight at winning the Bledisloe Cup for the first time in his career was tempered by a realisation his team remain a work in progress after their narrow win over Australia in Sydney on Saturday.

The Wallabies charge late but fall short of the All Blacks at Accor Stadium.

Australia seek to snap a 21-year hoodoo against New Zealand in the first Test in Sydney. Join Jonathan Howcroft for updates

After five drawn series and a heartbreaking Wallabies three-point loss, the fairness of the Bledisloe Cup format has been called in to question.