Perilously close in Sydney, the Wallabies are not going to have a better chance to break their All Black hoodoo than they will in Hong Kong.

Of the five tests the All Blacks will play on tour, this is the game where they will be most vulnerable.

No one knows whether Daniel Carter will be fit. Keven Mealamu, more important than many realise particularly when Hika Elliot will be on the bench, hasn't played since Sydney and even if his calf holds out, he'll be gasping by 60 minutes.

It's not often the All Blacks have such obvious chinks in the armour. The Wallabies surely realise that. Having lost the last 10 their analysis must be at an unprecedented level.

Wallabies coach Robbie Deans, a meticulous planner and researcher, will have pored over the micro detail.

The possible non-presence of Carter - he's hopeful he might start, but with his ankle still not quite right, an appearance off the bench is more likely - is the straw at which he will clutch.

Deans knows the value of Carter - having been hugely responsible for the All Black five eighths' development - and he saw how New Zealand lacked vision and confidence in Sydney without their chief playmaker.

Stephen Donald, should he start, has more experience and composure than Aaron Cruden, who got the nod in Sydney, but he's still fallible in a way Carter isn't.

If the Wallabies can keep the ball as they have in their last two tests against the All Blacks, they will heap the pressure on Donald. If he's operating on limited rations he'll possibly start to panic that every time he has the ball, he has to make it count and will lose his rhythm.

Deans's analysis will also have shown him that for 20 minutes after halftime in their last test, the Wallabies drilled the All Blacks into their own territory with a well executed kicking spree from Quade Cooper.

A repeat of this ploy wouldn't be a bad option. While it would concede possession, Donald is vulnerable to having his clearance kicks charged down. He's a little cumbersome and fast advancing Wallabies will be able to hound him.

But for all the analysis Deans will do, for all the optimism from Carter's likely non-appearance, the key, as it has been in the previous two years, is the speed at which the respective teams can acclimatise.

Not only will it be hot and humid in Hong Kong, both sides haven't played since they last met. Arguably, the All Blacks are better placed to settle quicker.

Their aerobic fitness has been outstanding all year and most of their 22 will have had some competitive football in the past six weeks.

The Wallabies, as was the case in Hong Kong 2008 and Tokyo 2009, might struggle to sustain their work-rate and wilt in the second half. This is when not having their own provincial championship really hurts them.

The final 20 minutes are possibly also where Sonny Bill Williams could hurt them. The All Blacks will want to unleash their new weapon before they get to Europe and a tiring Wallaby backline would be the perfect entry point.

But if there is trepidation at the prospect of facing Williams, Deans is hiding it. It's the rest of Australia that seems worried.

"Graham Henry will want to keep the foot on the throat of the Wallabies," said Reds coach Ewen McKenzie.

"He'll go with known quantities and not be too charitable. Sonny Bill will get a shot in Europe. He's a big ball-carrier who can bend the defence and offload - he's a handful. You'll have to be tackling him and anyone around him."

Hong Kong may well be the hardest game for the All Blacks on tour and it may be the Wallabies feel it presents their best chance to finally end their losing streak, but it will still take a monumental effort from the Australians.

Not that anyone within the All Black management team would ever admit this, but defeat might bring an element of relief. As much as the coaches would like to break the record for consecutive test records, there will be some angst about the growing distraction that record will become.

The ideal scenario is probably to win their next five tests, claim the record with 20 consecutive victories and then lose a test in next year's Tri Nations.

The thought of reaching the World Cup undefeated in 24 tests - which is what will happen if the All Blacks clean sweep on tour and the next Tri Nations - will fill Graham Henry with dread.

It will ramp unnecessary pressure on the players. It will see every test build-up at the World Cup dominated by questions about the winning run. The last thing the national team needs at a World Cup is more expectation.

Henry is also a believer that more is learned from defeat than victory. A sobering experience in Hong Kong could be a timely reminder that the gap between the All Blacks and the chasing pack is not as great as it was in June.

All year the coaches have talked about the need to keep evolving, to keep advancing their game-plan and defeat to the Wallabies would be a powerful means to focus minds and in a paradoxical way, increase pressure on one front and increase it on another.