Despite a run of disappointing results over the past two seasons and the failure of the Bok backline to score a single try in the recent Tri Nations, head coach Peter de Villiers has kept faith with the majority of the side that saw off the Lions in a mouth-watering three-match series in 2009.
And it is that familiarity and ability to perform when the chips are down, rather than recent form, that Muir believes will be crucial in New Zealand this month and next.
"We have an experienced squad, the guys are tried and tested, they've been under pressure situations before and their decision-making is key," said Muir, whose side begin their World Cup campaign against Wales in Wellington on Sunday.
"Once the World Cup gets going, you play a different team every week, so you have to concentrate more on honing your own game. We are going to be presented with a few opportunities, and we have to exploit them, and that is where the flexibility and decision-making comes in.
"Whatever happened last year and this year too, be it Wales' impressive warm-up games or our results in the Tri-Nations, Sunday is what counts. They can take what they want out of how we went in the Tri-Nations.
"I'm not worried about the lack of tries, it sometimes goes like that. You always want to score more tries but it is about winning games first. We have looked at ways to improve our try-scoring at the World Cup but the result is paramount."
Results at previous global gatherings make impressive reading for South African fans.
Victory in their first-ever World Cup in 1995 was followed by a semi-final appearance in 1999 and a second tournament triumph in 2007.
And if those stats aren't enough to prove to Wales that the Boks will present a massive challenge this weekend, then the one sided outcomes of 105 years of internationals between the two teams makes even more daunting reading for Mike Phillips, Shane Williams and Jamie Roberts and co.
Wales have won just once in 25 encounters since 1906 and have lost 12 straight games to the Boks since their solitary victory back in 1999.
And while the three most recent clashes between the sides have been close affairs, Muir was quick to point out that those November or June fixtures in Cardiff have often featured a far from full strength South African squad.
"I see there have been comments in the press about us not playing rugby, but we are all about results," added Muir.
"I think the end-of-year matches in Cardiff need to been seen in the right perspective. We tend to be under-strength on those tours because it is the end of a long year for us and fatigue and injuries have taken their toll.
"Sunday will be what it's all about."
Muir may be in confident and defensive mood ahead of the biggest clash of the opening round of the World Cup but that doesn't mean he is underestimating the Welsh.
Walescoach Warren Gatland is without Lions front rowers Matthew Rees and Gethin Jenkins - the former for the entire tournament and the latter for at least the opening Pool D encounter - but he can still call on 11 other Lions for the clash in New Zealand's capital.
And after impressive wins over England and Argentina in their final World Cup warm-up matches and with a star-studded backline likely to be on show at the Westpac Stadium, Wales will fancy their chances against the World Champions.
"Wales have played a lot of rugby, they're certainly a team that keep the ball in hand a lot and look to exploit opportunities. They're a well-balanced side that has really progressed with time," continued Muir.
"With the northern hemisphere sides, you tend to play them only once a year, and you play them as a national side and not a provincial side so you don't see as much as what different players have to offer. But we've had a lot of time to evaluate the Welsh and have a look at all their players individually.
"They have a lot of talent coming through, so there's quite a number of threats in the backline. You can see with results, they've been getting better and better."