South Africa's under pressure fly-half Manie Libbok said he has put "a lot of work" into his kicking at goal ahead of the blockbuster Rugby World Cup pool match between the defending champions and world-ranked number one Ireland.

The 26-year-old was named man of the match in the Springboks' opening 18-3 victory over Scotland but concerns were raised about the accuracy of his kicking at goal.

Libbok missed two penalties and a conversion which, in a game as tight as Saturday's contest at the Stade de France is expected to be, could prove costly.

The Springbok management may have heaped pressure on Libbok in calling up 2019 World Cup-winning playmaker Handre Pollard, as a replacement for injured hooker Malcolm Marx.

However, Libbok, whose open play is superior to Pollard's, seemed relaxed when he met with the media on Tuesday.

His mood chimed with the tranquility of the Springboks hotel golf complex far from the bustle of Paris in the village of Presles.

"My whole game is going to be important, every part of it -- if it is kicking for poles (posts), if it is kicking out of hand, if it is my attacking with ball in hand. Every bit of it is going to be important," said Libbok.

"I’m just working hard on my basic skills. Kicking for poles -- I've put a lot of work on it to get it right."

- 'Awesome game' -

Adding to the pressure cooker atmosphere, Libbok will be facing one of the greatest fly-halves of all time, Johnny Sexton.

Sexton, 38, has looked in fine fettle in the wins over Romania and Tonga, becoming Ireland's record Rugby World Cup points scorer in the first game and then his country's all-time highest scorer in the second one. 

"Johnny is a great player and he's done amazing things for Ireland over the years," said Libbok.

"But for myself, it's just focusing on myself and my game and preparing to the best of my ability to be ready to go on Saturday.

"I'm just looking forward to the challenge."

There is no back-up to Libbok should he be injured as head coach Jacques Nienaber has opted for a 7-1 split between forwards and backs on the bench.

This has raised eyebrows but it was a formula that worked well in the warm-up match with fellow three-time world champions New Zealand as the Springboks inflicted a record 35-7 defeat on the All Blacks.

Nienaber said it was a "calculated risk" and veteran wing Cheslin Kolbe, who starts, said they had faith in the management's selection decisions.

"We respect the decision of the coaches," he said.

"I'm sure there's going to be a lot of talking about it, but that's things we as players can't control.

"We just focus on the things we can control, and make sure that we don't get distracted by what's said.

"There is risk added as well, but we are quite fortunate to have players that can play in various positions and do as well as the player that's been selected to start there."

Kolbe, a star of the 2019 World Cup-winning team, said the squad as a whole were tight-knit and those playing on Saturday would have each other's backs.

"We just back each other up whenever we go out on that field and make sure that we play for each other," he said.

"We support each other, whether it's a good or bad decision."

Despite the hype surrounding the match Kolbe, 29, said he found it hard to describe how he felt approaching what was probably South Africa's biggest match since the World Cup final.

"That's four years ago. A lot has happened in that time and a lot has evolved in the team as well -- in a positive way."

For Libbok, though, the excitement was palpable.

"It is going to be an awesome game, an awesome experience to be honest," he said.

"It is the Rugby World Cup, it is the biggest stage in rugby."

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