The searing, humid heat of Brisbane is going to provide definitive proof tomorrow night as to whether the All Blacks are not only the best team in world rugby, but also the fittest.
Unlike the unseasonably cold New Zealand, Queensland is in the midst of a thermal blast. The temperature is expected to climb into the low 30s tomorrow during the day, with much of the heat likely to hang around until kick-off.
A brutal night awaits as both teams are keen to move the ball about, play with width and tempo. The All Blacks have shown all year they want to play like that, but the noises coming out of the Wallaby camp are similar.
For the first time this year, they appear ready to chance their arm: to open things up and revert to the swashbuckling style that has served them so well in the past.
When these two teams both cut loose, take risks and lose their inhibitions, the pace can be frenetic.
The demands of the game could be extreme - not one for the big units to enjoy and the contest in the tight will be fascinating not only around the collisions and set-pieces, but seeing which pack has the stamina, the aerobic capacity and conditioning to last the longest.
"We have looked at Australia and we know they have had hardships, quite a few injuries but they have got one or two back and they have got what would probably be the biggest forward pack they have ever put on the park," says All Black Steve Hansen. "We know that when we get our opportunities we will have to take them."
To take them, the All Blacks will need to be ruthless, clinical and focused in a way they weren't in their previous two encounters against the Wallabies. That challenge will be harder again due to the heat but this All Black side backs itself in terms of fitness.
They have in Nic Gill, one of the best, if not the best, conditioning coach in world rugby: a man who has trimmed the body fat off almost the entire squad. The man who the players believe has made this All Black side faster, more explosive and more durable than any of their predecessors.
Whether that is true will become clearer at Suncorp tomorrow night. It really will be survival of the fittest.