Ian Foster on the 'danger' that the All Blacks avoided

With his best poker face on, Ian Foster insisted he was "stoked" with New Zealand's return Bledisloe Cup performance as his All Blacks side snatched a last-gasp 23-20 win over Australia.

Richie Mo'unga kept the All Blacks' long unbeaten home streak intact with a 79th minute penalty in Dunedin, breaking Wallabies hearts again.

The Wallabies led for an hour in Dunedin after a rampaging two-try start, and brought the contest back to 20-20 with seven minutes remaining.

"Clearly we were second best by some distance in that first half," Foster admitted.

The first-half effort, described by some veteran All Blacks watchers as their worst half in many Tests, also created the dynamic that pleased Foster.

New Zealand hadn't had a close match in their three Tests this season, and the soon-to-be unemployed coach liked what he saw under pressure.

"To come back and show a lot of composure under that sort of scoreboard pressure, and to squeeze them and to win in the last few minutes, I think it's a great, great lesson for this team," he said.

"I'm stoked with the win.

"It's going to hold us in good stead for later on. We all know it wasn't perfect but we'll take it."

Viewed in isolation, the half-time scoreline of 17-3 to Australia was a damning indictment of Foster's decision to rest 12 players for their final home Test.

Effectively, it was the old guard of Aaron Smith, Dane Coles and Mo'unga who came off the bench to save the Test after a patchy showing from second-stringers like Damian McKenzie.

However, Foster said it was necessary to get some rugby into squad players' bodies ahead of the World Cup beginning next month.

"I know we made a lot of changes, more than we've had for a long time," he said.

"If we didn't do this game the way we did it, the danger was is that we'd have a number of players and then a World Cup squad that wouldn't have played a serious Test match for eight to nine weeks.

"So we knew what we're doing. And yeah, it was a bit nervous at half-time.

"But wow, the upside of it is we came through it ... that's a good sign too."

Two injuries also have the potential to give Foster headaches ahead of his World Cup squad naming on Monday.

Brodie Retallick and Braydon Ennor both limped out of the contest with knee injuries.

Foster did not elaborate on their severity beyond saying Braydon was "a bit sorer"

The always dour coach, who will be replaced by Scott Robertson after the World Cup, said the Test didn't change his opinion on the 33-man squad he will unveil in Napier.