New Zealand have never played two specialist spinners at University Oval, so the odds don't favour the recalled veteran Jeetan Patel and Mitchell Santner pairing up in the first test starting next Wednesday.
Patel is back after playing two tests in India in October, his first in three and a half years, when he faced South Africa at Cape Town and Port Elizabeth, with limited success.
But the 36-year-old, despite a test average of 48.48 for his 58 wickets in 21 tests, has caught the eye for the selectors.
His ability to turn the ball away from the lefthanders got him into the ODI series, with decent success.
South Africa's probable test top seven will include three lefthanders - opener Dean Elgar, JP Duminy and wicketkeeper Quinton de Kock - which enhances Patel's chances.
But University Oval has been a strictly one-spinner assignment in its seven tests since 2008, for the likes of Dan Vettori, Bruce Martin and Santner.
Santner is a lock in the side, even if his batting needs serious work. He keeps an end tight and his fielding adds value. So picking Patel and Santner would fly in the face of recent history in Dunedin.
Bustling Neil Wagner has won his race against the clock to be fit, after breaking a finger in a Ford Trophy game at the start of February.
He will be bursting to play against his former countrymen. Indeed his numbers demand his inclusion and he is forming a good, effective three-man seam attack with Trent Boult and Tim Southee.
Batsman Dean Brownlie and seamer Matt Henry have dropped out of the 13-man squad who prepared for the second Bangladesh test in Christchurch in January. Patel and Jimmy Neesham are in although Neesham is a strong candidate to be one of the two to sit the test out.
He made 71 in his most recent test, in Indore in October and has been in good touch in the ODI series. But with Henry Nicholls in at No 5 and coming off a good series against Bangladesh - plus a 36, 76 double in his only previous test against South Africa, at Centurion last year - Neesham squares off against Colin de Grandhomme for the fourth seamer role.
Neesham's batting is better; de Grandhomme's handier with the ball.
Wicketkeeper BJ Watling has made good runs in the last week for Northern Districts, suggesting he is fit, after concerns over a knee.
There's no place for Martin Guptill, as forecast yesterday and that's fair enough, his blistering 180 not out in the fourth ODI at Hamilton on Wednesday notwithstanding.
Those runs don't suddenly change the bigger picture in terms of Guptill's strength in white ball cricket vs his battles opening in tests.
He will be in the middle order when he returns to the Plunket Shield for Auckland.