South Africa’s stock rose on the back of a thumping 35-7 warm-up win over New Zealand in neutral London last week, a record defeat for the All Blacks, but Nienaber believes it will be all about fine margins at the World Cup.

"We have spoken about how close the contenders are," he told reporters on Friday.

"A lot of teams are in a position to win it and I believe it is going to be the most tightly contested World Cup in history.

"The key thing is to make sure you are 100% ready for a match. If you are one or two per cent off, the top teams will take advantage of that.

"We come in as defending champions, that is something we can’t hide from, you can’t shake that tag off. We must accept it."

South Africa are in a tough Pool B with world number one Ireland and an in-form Scotland, who they meet in their opener in Marseille on September 10th. Only the top two advance to the quarter-finals.

Nienaber says they are not thinking about anything beyond the Scots.

"All our preparation has been about Scotland and nothing else. They are a very fit team and that is why they can play the game until the 85th minute. It is probably one of their big strengths.

"They also have a solid set-piece. To play with the amount of possession they have, with the rhythm they get and ability to run the ball wide, you need a very good set-piece."

Nienaber believes South Africa are better placed for success than four years ago, with a longer preparation time for this tournament and a massively improved squad depth.

"When we (Nienaber and director of rugby Rassie Erasmus) took over the team in 2018, there was limited time to prepare for that World Cup. We had 18 test matches," he said.

"This time round we have had four years, even if one was taken away by COVID. Our main aim has been to get as much squad depth as we can because we have always said that defending the World Cup takes a squad effort."