Ireland showed in New Zealand that they have the fast-paced game to out-sprint one of rugby's superpowers.
They had to do it as long distance runners at the Aviva Stadium on Saturday.
And the outcome was the same when they crossed the finish line ahead of the mighty Springboks.
READ MORE: Ireland withstand Boks storm to lay down marker in thriller
The first half was carnage as the visiting World Cup champions played their normal attritional game and the hosts, the world's top ranked side, stood up to that challenge.
Four players had been replaced due to injury by the start of the second half - three on the home side.
They were victims of an absorbing if low-scoring opening period that saw Ireland's pack go toe to toe with the Boks' bomb squad and hold their own.
Then South Africa blinked first.
"It wasn’t a fast game," observed Ireland supremo Andy Farrell. "There were a lot of stoppages within the game because of the nature of the physicality.
"And if you add on top of that the water breaks - I just don’t get it.
"Who needs a water break in Dublin in November? I think the marathon didn’t have as many breaks."
Opening try scorer Josh van der Flier said the most pleasing aspect of the victory was that Ireland had to change tack.
"We’ve done well with running rugby in New Zealand, who like to play the ball a bit," said the flanker.
"Teams like South Africa will look to do the opposite, make it a tight game, more of a grind, a physical test.
"So we can come to expect it. It was physical but we felt good fitness wise. We just had to keep going, keep fighting and stay in there.
"It's good to come away with a win in a game like that, a good learning curve. We’d take a lot from that."
Farrell had high praise for Ireland's scrum and maul defence in difficult moments.
Then Jamison Gibson-Park proved a game-breaker when he replaced Conor Murray, whose 100th Ireland appearance ended prematurely.
Making his first appearance of the season, Gibson-Park's speed of thought made a vital difference.
Ireland hit the Boks with two tries in four minutes early in the second half - the first off a lineout maul, the second a superb piece of clinical finishing off a counter-attack.
Then they then had to show the resolve to close it out after conceding two tries themselves in the exciting closing stages.
"The win builds on our confidence in different areas, because it’s a different type of game than has been thrown at us over the last couple of years," acknowledged Farrell.
"That’s definite. But having said that, I think the belief was there anyway.
“The forward pack were excited at what was coming against them and I’ve constantly tried to drill that into them the whole time, that this is where you want to be.
"You want to be tested, to find out about yourself, to be in a state of mind that’s ‘well, it doesn’t get better than this, let’s have a go at it’.
"I’m certain that’s how the forward pack felt this week."
There was no grandstanding and no evidence of over the top celebrations afterwards.
This was a big scalp but it was more job done, move on.
“It is and, well, they know they were in a hell of a Test match," said Farrell of his players. "There’s a bit of relief to get the victory."
But the squad did make a fuss of Murray and Jimmy O'Brien, who was at the other end of the scale having impressed on his Test debut as Stuart McCloskey's first half replacement.
"We make a lot of that kind of stuff," said Farrell. We’re unbelievably privileged to be part of this set-up when things like this happen.
"Eight of them have happened as far as the 100 club is concerned and for us to be able to get Conor’s family in, and Jimmy’s family in, during the week, it’s great for us all.
"We’re so pleased we managed to get over the line to make it extra special for them.
"But at the same time, from what we talk about and what we’re trying to achieve with our preparation, there is more in us, you know? That's the realisation."
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