Springboks' 12-match streak and world No.1 ranking on the line against All Blacks at Ellis Park

South Africa’s 12-match winning streak and their grip on the World Rugby No.1 ranking face their sternest test on Saturday, when the Springboks host New Zealand in the opening fixture of the four-match Rugby’s Greatest Rivalry series at Ellis Park in Johannesburg.

The Springboks enter the series ranked first on 93.96 points, holding a 1.68-point advantage over the second-placed All Blacks. The margin is tight enough that a New Zealand victory alone would be sufficient to send them back to the top of the rankings for the first time since September last year — a win by more than 15 points would hand them a 1.82-point lead heading into the second Test in Cape Town.

South Africa, by contrast, have the opportunity to make their position considerably more secure. A win by 15 points or fewer would extend their cushion to 3.34 points, while a victory by more than 15 would open up a 4.18-point lead — enough to guarantee they retain top spot even if they lose the second Test. Neither side can drop below second place this weekend.

The Springboks’ current winning run — their longest under Rassie Erasmus and their best sequence since a 13-match streak between 2007 and 2008 — was extended most recently with a 17-10 victory over Argentina in Buenos Aires, tries from Edwill van der Merwe and Cameron Hanekom keeping their Nations Championship campaign unbeaten. South Africa have now won 20 of their last 22 Tests, lead the Nations Championship for points scored with 130, and have crossed for 20 tries in three matches. No team has made more entries into the opposition 22, with the Springboks recording 43.

New Zealand arrive in equally strong form. Under Dave Rennie, the All Blacks won all three of their Nations Championship fixtures against France, Italy and Ireland, trailing South Africa only on points difference in the southern hemisphere standings. They have led the competition for carries, metres gained, defenders beaten and passes completed.

Central to that attacking output has been Will Jordan. The full-back has scored six tries in the Nations Championship and now holds 51 Test tries from 57 appearances, having surpassed Doug Howlett’s long-standing All Blacks record.

South Africa hold the recent edge in the rivalry, winning five of the last six meetings, and the two sides have historically been separated by the smallest of margins — the four Tests before last year’s encounter in Wellington were all decided by seven points or fewer.

That Wellington match, however, was an outlier. The Springboks stormed to a 43-10 victory, the heaviest defeat in All Blacks Test history, after New Zealand had led 10-7 at half-time. Whether Ellis Park produces a similarly one-sided outcome or the tight, attritional contest the rivalry more typically delivers, the World Rugby rankings will look different by Saturday evening.