The Lions centre partnership of Brian O'Driscoll and Jamie Roberts will have their toughest examination to date when they try to get the better of Springboks pair Jean de Villiers and Adrian Jacobs in the Durban duel.
The Irish-Welsh axis impressed in the Lions' biggest win of the 2009 tour over the Golden Lions and they also managed to punch some big holes in the Sharks defence.
Lining out alongside Roberts for the third time on tour, O'Driscoll feels the duo can improve significantly on those recent performances.
"We're a work in progress. I don't think you've seen all we're capable of as a combination yet," he said.
"Jamie's multi-skilled and it's nice for an outside back to be playing off an inside centre like that. He's a big physical guy, but he has great skills too.
"People don't give him the credit he deserves in that regard. He'll keep the Springboks' defence honest, and hopefully he'll create a little room for me."
O'Driscoll has faced South Africa on five occasions for Ireland at Test level, losing three-in-a-row between 2000 and 2004 before the 'Boks were defeated at Lansdowne Road in both November 2004 and 2006.
Jean de Villiers was a centre in the South African side that lost 32-15 back in 2006.
That was the only time O'Driscoll has had the big Stormers centre as a direct opponent, while the Ireland captain has not clashed with Jacobs since they played against each other at the 1999 Under-19 World Cup.
With Jaque Fourie proving back-up on the bench, the 'Boks midfield has quality stamped all over it.
O'Driscoll said: "I've watched them (de Villiers and Jacobs) previously, and had a look at some footage of them recently, and both are very good footballers.
"For a big man Jean is very skillful and gives them great go-forward.
"Jacobs knows how to get over the try-line. He has quick feet and good hands, and mixes his game up very well. I presumed that they were going to be the starting midfield pair.
"They're fortunate to have three really top class centres, and indeed Wynand Olivier falls into that category as well.
"It's a difficult decision for Peter de Villiers to make, but a nice one at the same time."
O'Driscoll has experienced wide-ranging emotions in a Lions jersey. In 2001 he scored a sublime solo try as the Lions beat Australia in Brisbane only to lose the series 2-1.
In 2005, he faced down the haka as captain but lasted only 40 seconds of the first Test against New Zealand when he suffered a dislocated shoulder.
2009 has already been a bountiful year for the Dubliner, with Grand Slam and Heineken Cup successes and individual honours, but being part of a Test series-winning Lions series is an accolade that has so far eluded him.
With that goal very much in his sights here on Springbok soil, he said: "Defeat is not an option for me, I want to be part of a winning Lions series.
"As I've said from the start, I have no interest in coming on tour and being part of a squad that loses the series.
"I've been there and done that. I'd like to be part of a team that creates history and does something special.
"That said, I'm trying to not put too much pressure on myself or the team. I don't over-think things, and I'm just trying to enjoy it.
"This is where you want to be, playing with the best players from Britain and Ireland against the reigning World champions."
And is he confident that the Lions can achieve the desired result this weekend?
"We certainly need a big amount to go right for us. But I feel as though we have the capabilities and individuals to create a huge amount of chances, as well as those with the work-rate and mentality that you need to beat the Springboks."