Ireland coach Andy Farrell praised his "outstanding" pack for emerging from one of the toughest tests in world rugby against the always physical Springboks with a 19-16 victory that added to the top-ranked team's growing momentum.
In a relentless first period, Ireland went toe-to-toe with a South African forward pack that loves to grind down opponents, before striking first in a more open second half and remaining resilient to rack up another big win.
After playing scintillating rugby to give New Zealand their first back-to-back home defeats in 24 years in July, Ireland had to adapt their game for the world champions with pure guts seeing them through, captain Johnny Sexton said.
"We've got resilience, guts, character ... Wow, I thought the character of the side was immense," Farrell added, describing the bruising encounter as "a proper old-fashioned test match".
"The character that our lads showed, some of them having not played much rugby at all, bit of adversity with injuries etc and then not missing a beat with the first game of the season. To say it's pretty pleasing would probably be an understatement."
Farrell singled out scrum coach John Fogarty and forwards coach, former captain Paul O'Connell, for praise.
"The forwards, these are the type of games they want to be involved in, to test themselves and to a man they all stood tall. They were outstanding tonight."
South Africa captain Siya Kolisi and coach Jacques Nienaber said Ireland fully deserved their win, with Nienaber saying the attacking game Farrell had fine-tuned in recent outings could disguise how strong Ireland can be up front.
Nienaber was left to rue his side's goal-kicking after flyhalf Damian Willemse struggled early on before handing over kicking duties to fullback Cheslin Kolbe, who was unable to convert either of South Africa's two late tries.
Ireland on top
Ireland came out on top in a physical battle against South Africa with a 19-16 victory that handed the top side in the global rankings a psychological boost over the world champions ahead of their title defence next year.
After a ferocious first 40 minutes that had more injuries than clean line breaks, the game opened up early in the second half with quickfire tries from Josh van der Flier and Mack Hansen that put Ireland 16-6 ahead.
The host's defence finally buckled 13 minutes from time when South Africa lock Franco Mostert stretched over but their lack of a recognised goalkicker proved costly as a Johnny Sexton penalty meant a 76th minute Kurt-Lee Arendse try was not enough.
"It was a real, proper test match, South Africa pressure you in way that not many other teams do," Ireland captain Sexton said in a pitchside interview. "We dug in, we didn't play at our best but sometimes they don't let you."
That pressure was clear in an intense start when Ireland had to survive a 17 phase South African blitz, an early indication of how well equipped Andy Farrell's men were to weather it.
With chances few and far between, Ireland failed to take advantage of a Cheslin Kolbe yellow card and it was the 14 men who were guilty of not putting points on the board. Damian Willemse, who struggled all day at flyhalf, badly missed a shot at goal.
Sexton was never going to miss from point-blank range shortly before the break after the first multi-phase attack of the game for Ireland which began with a Conor Murray lineout break that turned back the clock on the scrumhalf's 100th cap.
However that was it for the landmark appearance after he pulled up in the process.
South Africa lock Lood de Jager left the field at the same time cradling his arm after the attritional encounter earlier ended Stuart McCloskey's impressive start with a similar injury, a cruel blow in just his seventh Irish cap in seven years.
Kolbe, starting at fullback for the first time, added another unfamiliar role to his day when he took over kicking duties and levelled with a penalty in front of the posts.
Ireland prop Tadhg Furlong joined the injury list when he failed to emerge after the break but they made the early breakthrough when Van der Flier sneaked over the line when it looked like the Springboks had driven the Irish pack into touch.
The hosts struck again three minutes later, turning the visitors over on one wing before Hansen finished off on the other to make it 16-6.
South Africa emptied their bench on the hour and one of the those replacements, Mostert, got them back into the game but Kolbe failed to add the extra points.
Sexton made up for two missed conversions with the crucial touchline penalty and Ireland followed up their first ever three-test series victory in New Zealand in July with another important win against a team they will face again in the World Cup pool stages in France in 10 months' time.
- Reuters