If things go wrong, any idea that "never mind, we'll always have Hobart" will ring hollow.
There are parallels between the challenge New Zealand faced in Tasmania and the job awaiting them today.
A short recap.
New Zealand had been belted in the first test at Brisbane. Having won the toss, they were reeling at 96 for five, recovered, had Australia in trouble at 91 for three, gave batting kingpin Michael Clarke three lives en route to 139, before losing the plot with the bat.
When debutant quick James Pattinson took five for seven in 6.3 overs on the fourth morning, the game was quickly up.
A few days later at Hobart, New Zealand bowled splendidly, albeit in conditions which could not have been improved for seamers had a team of pacemen sat down and designed them to suit, and edged out the Aussies by seven runs.
It broke a 26-year drought of test wins across the Tasman, and was New Zealand's first victory over the neighbours since 1993. It mattered.
The four-seamer policy had worked a treat and did so again against far less demanding opposition when Zimbabwe arrived in late January.
Now, after rain had left the first test even stevens, having had their opportunities in the second test at Hamilton last week, New Zealand's batsmen dropped their lines so badly the game was done inside three days.
Losing five for none in the first innings was nothing less than shameful but the bowlers had South Africa reeling at 88 for six before once again the initiative was surrendered. Weak batting second time round did for New Zealand.
Within pockets of that match, New Zealand held sway.
The problem was they didn't do it for long enough.
And so South Africa, who are no slugs at seizing a situation and never lie down, knew if they squeezed hard enough, New Zealand would be like pips flying out of an orange.
So have the lessons been learned? The next few days will tell.
Patience with the bat, accuracy in planning and execution with the ball, and actually pressing home an advantage will help.
New Zealand will need to dig deep, which sounds an over-simplification.
South Africa, after all, have shown they are a strong, well-rounded, experienced outfit. Their pace trio of Dale Steyn, Morne Morkel and the ever-demanding Vernon Philander are all in the top 12 on test bowling rankings.
Jacques Kallis is a top-class foil and they possess decent spin, too, in Imran Tahir. Their batting is resourceful and skilled.
Which is not to say they are unbeatable.
Remember, no one gave New Zealand a prayer at Hobart. They made their luck and in a low-scoring contest they prevailed through resolve and utter determination.
No less is needed now if this test season is not to be remembered as one which began spectacularly but ended with a whimper.
NZ V SA
Basin Reserve, 10.30am today
New Zealand: (from) Ross Taylor (c), Martin Guptill, Daniel Flynn, Brendon McCullum, Kane Williamson, Dean Brownlie, Dan Vettori, Kruger van Wyk, Andrew Ellis, Doug Bracewell, Tarun Nethula, Trent Boult, Mark Gillespie, Chris Martin.
South Africa: Graeme Smith , Alviro Petersen, Hashim Amla, Jacques Kallis, AB de Villiers, Jacques Rudolph, Mark Boucher, Vernon Philander, Dale Steyn, Morne Morkel, Imran Tahir.
Umpires: Aleem Dar, Richard Kettleborough
