Ireland's epic 13-8 victory over defending champions South Africa had all the ingredients to suggest they could at last be able to erase years of Rugby World Cup disappointment.

Andy Farrell's world ranked number one side not only ensured they remained at the top of the rankings -- the Springboks would have replaced them if they had won -- but showed they have the mettle to become the first Irish team to go beyond the quarter-finals.

Tough tests lie ahead as Farrell and captain Johnny Sexton said not least if they beat Scotland in a fortnight and top Pool B their quarter-final opponents are likely to be three-time champions New Zealand.

AFP Sport picks out three key things which augur well for the Irish going forward:       

Aki the centre of excellence

Redemption is often sought after but not always achieved. However, Bundee Aki can say he has redeemed himself.

The 33-year-old New Zealand-born centre was a downcast figure at the 2019 World Cup after he was sent off in the pool game against Samoa and was suspended for the quarter-final hammering by the All Blacks.

Four years on he is all smiles.     

"He's having a hell of a tournament," Ireland scrum coach John Fogarty said of Aki on Sunday.

That he is. Four tries in the first two pool games and endless hard hitting tackles, the barrel chested back took it up a notch against the Springboks in what was his 50th cap.

Arguably he flicked the switch that transformed the Irish mentality in the match.

Hard pressed in their 22 midway through the first-half he prevented the Springboks going over for a try with a crunching tackle.

Within a minute, ball in hand inside the 22, he sashayed away from the tackler and produced a lung-busting run into the opposing 22.

The confidence it gave his teammates eventually led to Mack Hansen's try.

"He is a great character," said Fogarty.

"He is very, very clear in his mind of what he wants to do which does not go unnoticed by the players.

"That gives them so much energy, as they see him picking guys off the ground, he is vocal on the field, has real punch in his tackles and carries.

"He makes people feel good on the field."

Learn to stay ahead of the pack

Johnny Sexton is not a killjoy but just like one of his many qualities as a captain and a player he is a pragmatist.

Whilst both many Irish and non green jersey wearing pundits and fans were purring about the victory suggesting the Irish were on their way to being crowned world champions, Sexton was having none of it.

The 38-year-old has experienced enough disappointments to go with the great moments to know that against the South Africans there were errors that if the Springboks had been clinical they could have secured the win.  

Instead the Irish extended their record Test winning run to 16.

"We're in a good place but when you're on an unbeaten run, you have to keep your feet on the ground and keep striving for a better game," he said.

"Teams will see that tonight and go 'this is how we get after Ireland’ and we just need to keep learning on the run.

"To go and win a World Cup, you need to keep learning on the run, week on week, and make sure that you're learning in victory as well."

Fans-tastic -- Ireland's 16th player

The flights back to Ireland and elsewhere on Sunday will be filled with bleary-eyed supporters who celebrated long into the night.

However, they leave with praise ringing in their ears from Sexton.

The deafening cheering backed up by renditions of the 'Fields of Athenry' and the more innocuous 'Ole, Ole, Ole!' during the match were invaluable.    

"I've never, ever seen a crowd like that," said Sexton.

"Someone said there was 30,000 but it was more like 60 and they were insane throughout and they gave us the lift that we needed.

"They probably saved for four years to come here and it is something we refer to all the time and I mean that.

"We played for them and they gave us the edge tonight, fair play to them."

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