Sometimes big occasions can live up to the hype.
This meeting of the reigning champions and world No. 1 side was hotly anticipated and widely tipped as a contest that could be replayed next month in the final.
On this evidence, not many neutrals would complain were that to happen.
A brutal, breathless 80 minutes was fought with a level of intensity and skill that underlined why these are the top two teams in the world rankings.
If this was an acid test of their respective title credentials, neither will come away from a bruising Parisian battle feeling that World Cup glory isn’t a very achievable goal.
But it was the Irish who made a huge statement with a performance that provided a reminder – as if one were needed - of what makes them so special.
They soaked up all the famous power the Springboks and their controversial bench of seven forwards threw at them and gave it back with interest.
They pinched and pilfered at the breakdown, they executed in the red zone, and - crucially, as it turned out – they kicked their points with composure from the tee.
A mesmerising night in the City of Love ended with a raucous outpouring of just that from the enormous Irish support in the Stade de France, who will believe now more than ever that this could be their time.
For Scotland, the result undoubtedly makes things more complicated.
A bonus-point victory over the Irish will almost certainly be required in Paris in two weeks’ time, and it’s going to take something very special to end Ireland’s record winning run, which now stands at 16 games.
Ferocity was expected, and ferocity was delivered on a frightening scale, from the first whistle.
The two sets of players tore into each other, Ronan Kelleher setting the tone with a thumping hit on Damian Willemse with the first collision of the game.
Ireland earned the first opportunity with an early penalty in kickable range but instead, somewhat surprisingly, opted to kick to the corner – a decision they quickly regretted when their line-out was pinched.
Up went the Springboks to the other end, where they took three points from the boot of Manie Libbok when on offer.
The battle for physical dominance never relented, with Mack Hansen taking a huge double-hit and Damian De Allende carrying so hard into Gary Ringrose that the crowd groaned in pain before the Irish centre went off for a Head Injury Assessment – which he passed.
Crash. Bang. Wallop. The battle at the breakdown was every bit as intense as expected, but Ireland’s attacking shape was asking questions and a superb break from the formidable Bundee Aki took them deep into South African territory.
Sexton opted for ambition again when the referee raised his arm in Ireland’s favour, kicking to the corner, but this time it paid off as green shirts flew at the Springboks line before choosing the opportune moment to fling it wide for Hansen to dot down.
The second half continued where the first had left off, and Faf de Klerk was incredibly unlucky when an ambitious penalty attempt from inside his own half clattered off the post.
South Africa started to empty their opinion-splitting 7:1 bench and saw immediate results, winning a scrum and shifting the ball wide quickly for Cheslin Kolbe to score, but Libbok’s missed conversion made it just a one-point lead for the Boks.
A big win in the scrum just outside the 22-metre line was met with a huge roar from the 30,000-strong contingent of Irish fans, and Sexton gobbled up the opportunity to nudge his side back in front from the tee.
Libbok’s kicking came in for criticism in the wake of the win over Scotland two weeks ago, and the fly-half’s inaccuracy was again costly when he missed a penalty that would have put his side back in front.
De Klerk took kicking duties back for the next long-range effort but had no more luck as the Irish hung on despite a rising penalty count.
For all the frustration at their problems from the tee, the Springboks wrestled the momentum into their favour going into the closing quarter but couldn’t turn territory into points against a stubborn Irish defence.
They were made to pay when Ireland won another scrum five metres in front of the Springboks posts, which replacement Jack Crowley knocked through for a five-point lead going into the final three minutes.
A nervy conclusion unfolded when South Africa mauled towards the line from a five-metre lineout, but referee Ben O’Keefe signalled a turnover to the clamour of Ireland’s vociferous support.
