The Boks’ 31-point margin of victory – allied to a bonus point for scoring four tries – means that for Scotland and Ireland to go through at the South Africa's expense, the former needs to beat the latter by 21 points while Ireland score four tries in defeat.
In that scenario, all three teams would have 15 log points; Scotland would progress with the best points difference, while Ireland would oust the Boks by virtue of having won the head-to-head match.
As Scotland have lost their last seven matches against their celtic rivals it is preposterous to think that they might now achieve such a result after the Boks eventually took care of business by claiming the bonus point in the 49th minute as they racked up seven tries in total against Tonga.
But it was not easy in front of a Tonga-favouring crowd of 60 387. The ghosts of Lens haunted the opening quarter as Tonga dominated possession to recall the nail-biting affair of the 2007 tournament when the Boks escaped by the skin of their teeth with a 30-25 victory.
The Pacific Islanders opened the scoring with a third minute penalty goal by flyhalf William Havili after a shaky start by the Boks, who missed the kick off to set an unhappy tone.
The Boks hit back in the fifth minute from their only visit to the Tongan 22 in the opening quarter, when the ever alert Cobus Reinach (scrumhalf) took a quick tap at a five-metre penalty and ran in in the corner.
Their next visit was only 15 minutes later after repeated Tongan attacks from a succession of penalties had been repulsed. Andre Esterhuizen made one of several tackle busting runs to give field position, but a try for his centre partner Canan Moodie owed much to good fortune. Handre Pollard’s pass bounced forward off the head of prop Vincent Koch for Moodie to collect the loose ball and elegantly swerve past the last line of defence.
The Boks were now beginning to assert a measure of control and Deon Fourie claimed a second Springbok try at the back of a driving maul as the Tongan pack began to falter. Pollard converted all three – two from wide out on the right – to give the Boks a 21-3 lead before Tonga were let back into the game.
A penalty for offside as a Tongan attack was broken up by offensive defence on halfway was turned into a lineout five metres out and after half a dozen phases, 151kg prop Ben Tameifuna flopped over the line from barely a metre.
The more dynamic Jesse Kriel – on as a replacement for wing Makazole Mapimpi following a head clash in which Tongan scrumhalf Augustine Pulu was lucky to escape a yellow card – drove in from close range after a succession of drives had exhausted Tonga’s defence.
Tongan right wing Fini Inese crossed in the corner from a long looping pass after repeated attempts to beat down the front door from more drives had failed.
The Boks responded in the left hand corner through Willie le Roux from Moodie’s pass after Manie Libbok – on for Pollard – had dislodged the ball in a tackle as Tonga tried to run out of defence.
Marco van Staden, who replaced Siya Kolisi but packed down at hooker with Fourie moving to flanker, added the sixth try in similar style as the match entered the final quarter and the Boks three times looked on the verge of claiming a seventh – once through Esterhuizen and twice through wing Grant Williams – before a break out from their own half by replacement flyhalf Patrick Pellegrini ended in a third for Tonga.
The seventh finally arrived in the final minute when Kwagga Smith’s all action play was rewarded with a try under the cross bar. Libbok landed his third conversion from three attempts to round off a challenging but ultimately successful night.
Springboks 49 (21) – Tries: Cobus Reinach, Canan Moodie, Deon Fourie, Jesse Kriel, Willie le Roux, Marco van Staden, Kwagga Smith. Conversions: Handre Pollard (4), Manie Libbok (3)
Tonga 18 (8) – Tries: Ben Tameifuna, Fine Inisi, Patrick Pellegrini. Penalty goal: William Havili.