Defending champions South Africa opened their World Cup account with a hard-fought 18-3 win over Scotland and followed that with a 76-0 demolition of Romania.
Ireland, meanwhile, have had comfortable bonus point wins over Romania and Tonga.
Saturday's contest in front of a sold-out 80,000-capacity Stade de France will be a different level entirely for both teams, matching the intensity and quality of the tournament's opening fixture between hosts France and New Zealand.
"There's a lot at stake," De Klerk said in Thursday's press briefing.
"We've always known this game was going to be there. It's a World Cup match and we all know what's at stake
"As a group, we are very well prepared and very eager to get going and get it over with."
The Springboks have won 18 of their 27 previous matches with Ireland but it is the Irish who have held the upper hand in recent years, winning four of the last six meetings, including a 19-16 victory in Dublin last November.
Following that the Irish went on to win the Six Nations Grand Slam and claim the number one ranking in the world.
"Obviously you get confidence from winning, you learn how to win and they've done that," says De Klerk.
"If you learn how to win it just comes easier.
"Their biggest strength is their accuracy surrounding their whole game.
"They've got a very balanced game and a very high skill set. They create quick ball through dominant carries and great ruck reaction. And they have a good set-piece.
"The guys that are playing are very experienced. They've been there, done that and the group is predominantly the same. They know each other really well.
"We just need to try and break all those connections up."
De Klerk returns to the number nine jersey after filling in at fly-half against Romania but with the coaching team of Rassie Erasmus and Jacques Nienaber opting for a 7-1 forward split on the bench, he will be needed to cover if anything happens to Manie Libbok.
"I don't think it will happen but if it needs to, I am very comfortable stepping up," said De Klerk.
"I played there before in my career and at schoolboy level. This is obviously a lot bigger but I've been training there since we got together as a group. I've trained there a lot."
Against Scotland, the effusive scrum-half with the shank of blond hair also took over from Libbok as goalkicker.
"That only happened once," he says. "We just felt I should take over. Manie was playing amazing rugby, got man of the match. We didn't want to make that a thing.
"We scored a try and we told Manie 'you just focus on your game and I'll take over from here' so that was it. It's not like if he misses three kicks I automatically take over.
"We all know how well he can kick and we have full confidence. It's really not an issue. He'll probably go 100 per cent this weekend."
De Klerk also believes that the buzz in the Springbok camp is on a par with that of 2019 when they went on to lift the World Cup for the third time.
"Definitely. We have lost a few boys along the way but we've also gained a lot of players, experienced players and some magic.
"The majority of the group has stayed the same, which is great for cohesion but the guys that have come in have played amazing rugby and adjusted to the culture so well and been an asset to the team.
"They aren't just great rugby players but great people. That's something that we really try and focus on.
"In a World Cup, it's important we are all great mates and there are no issues inside the team. If we keep it like it is, then we are as tight as 2019."