Get hold of the ball and we'll "kill them".

That's the simple formula from World Cup winning coach Sir Graham Henry, who says equal possession will produce a Bledisloe Cup victory for the All Blacks on Saturday night.

Henry told Radio Sport All Black fans should be concerned after the walloping Australia dished out in Perth.

"Of course we should be worried…the All Blacks will be worried and so they should be," he said.

"They were soundly beaten by a very good Wallabies side.

"I think the All Blacks gave away eight penalties on the weekend which is not a lot in the normal game but Australia only gave away four…which has a pretty big effect on the result I reckon.

"They had 11 lineouts, we had four – they had 11 starts in lineouts. So we lacked ball. We only had 30 per cent I think but with that we scored four tries which was a good result really.

"So we just need more ball. If we can get 50 per cent plus we are going to win the game, because we've got the players to use that ball effectively.

"And our defence believe it or not was better than the Australians - they had 70 per cent of the ball and scored six tries.

"We need to play the game correctly so we get more than our share – if we get 60 per cent we're going to kill them."

Henry hopes coach Steve Hansen, his old deputy, sticks with Richie Mo'unga at first five-eighths, leaving Beauden Barrett at fullback.

"Beaudie is a fantastic player whether he plays 10 or 15, and Richie Mo'unga has been the form five-eighth for a couple of years," said Henry.

"His (Mo'unga's) composure under pressure is hugely impressive. He's also a bit of a game breaker because he can take on the line, he's a good goal kicker, and he just needs time in the saddle I think.

"He's a young player internationally…I've got no problem with the strategy, it just needs time. Yeah, I think there's time."

Henry said the All Blacks needed to get "in the zone" and suggested avoiding social media in a massive week like this would help to eliminate distractions.

Whether the All Blacks shut themselves off or not, they understood the pressure on them.

"There's no hiding from the (country's) expectation and I think that's what brings out the best in the All Blacks," he said.

"It's important they control their environment and put a filter on it, particularly in a game week and in this situation where they need to produce a fantastic performance.

"It's very important they get into the zone on the weekend and are right on the job. That's all about the right preparation."