All Blacks captain Kieran Read is braced for a lung-busting, end-to-end spectacle against the Springboks at Loftus Versfeld on Sunday morning (NZ time).
While former South African captain Victor Matfield has ruled out altitude as a factor in the Rugby Championship clash, Read insists it will take a mental toll, as much as a physical one - especially given the style of play preferred by both teams.
"It's a factor, but it's a factor for both teams," he told media, after Saturday's captain's run.
"For us, we've acclimatised this week and when you're out on the field, you have to push yourself through it. It's a mental game as much as a physical game.
"It's just harder to get the air in your lungs - that's just the nature of altitude.
"It doesn't mean you can't perform at your level, it just makes it more mentally challenging, because you are put under mental fatigue."
In the corresponding fixture 12 months ago, played at Cape Town, the All Blacks and Springboks played an extra 10 minutes at the end of the first half, seemingly oblivious to the siren, as they piled on phase after phase of attack and counterattack.
During that period, New Zealand lost first-five Beauden Barrett (concussion) and wing Nehe Milner-Skudder (shoulder) for the rest of the match.
Read hinted his players were ready for more of the same this time.
"Both teams have shown a willingness to really attack," he said. "It's been a few years since we've played here at altitude, but it always seems to be a ding-dong battle.
"I'm sure we'll need to go the 80 minutes or over it, if we need to.
"The guys are excited by that challenge, so hopefully it will be a great spectacle."
After their surprise 36-34 loss to South Africa in Wellington three weeks ago, the All Blacks have been eying this encounter as a chance for payback, but Read warned their rivals would be even better this time.
"We leaked 36 points, they leaded 34 points, so it was a pretty open game," he said.
"Both our defences improved last week. They'll be better there, so we have to find more ways to break them down."
After off-season surgery on his back, Read was rested for last week's trip to Argentina, but insisted he was 100 percent fit for this clash.
"The back's feeling really good. It was probably great foresight from the coaches and, for me, being back in the squad is pretty invigorating.
"It's 100 percent when I'm out there playing, but travel and a few things can stir it up.
"It's probably 12 months before you start feeling like you were before, so there's a few months to go in that process."
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