Mike Ross will play pivotal role for Ireland: Cronin
Sean Cronin believes Ireland will need to draw on fit-again tighthead prop Mike Ross "big-time" against the powerful Springboks.
Hooker Cronin has stepped into the breach after Rory Best failed to beat a calf problem, forming an all-Leinster front-row with Ross and loosehead Jack McGrath.
Ireland must take on Heyneke Meyer's formidable Springboks without injured prop trio Cian Healy, Marty Moore and Nathan White, while Ross returns after missing a month through groin trouble.
Cronin boasts 35 caps but will make just his seventh Ireland start in tomorrow's Dublin Test, keen to prove himself against a Springboks squad containing "two of the best hookers in the world".
"Mike brings a valuable amount of experience and it's a good factor that the three of us play together," said Cronin.
"All of their starting front-row play for the same Super Rugby franchise as well.
"They've a huge amount of experience, so we're going to need Mike big-time on Saturday.
"He has been able to do the scrummaging work.
"It was a bit of chop and change last week but ever since we came back in at the weekend everyone's been working in their own core groups, scrummaging and lineouts, so we've had plenty of time together.
"And again, myself, Jack and Mike play together in our club rugby, which is great.
"So at least it's not too much of new surroundings there, we're used to each other and that's a major positive.
"In terms of Rory (Best), I think it's just the fact it's a calf strain and it's very position-specific.
"He needs his calf in a lot of aspects of the game for a hooker of course.
"It's just great they've given me a chance, I'm really looking forward to it."
Cronin's ball-carrying threat could help Ireland offset the loss of power-runners Healy and Sean O'Brien against the notoriously physical Boks.
The 28-year-old has hit rich form for Leinster this term, and is relishing the opportunity to face South Africa's hooking giants Bismarck du Plessis and Adriaan Strauss.
Leinster's Richardt Strauss is back in Ireland action for the first time since June 2013 in taking a seat on the bench, after a year out of the game while battling heart surgery and a hamstring torn off the bone.
The South Africa-born 28-year-old is likely to face his cousin Adriaan if both replacement hookers join the weekend fray.
"I just see it as a massive opportunity: they are a class outfit," said Cronin.
"They have two of the best hookers in the world in Du Plessis and Adriaan Strauss as well, so whichever one of them was going to start it would be a huge challenge for me.
"I see it as an opportunity to pit myself against one of the best players in the world, and hopefully I can give a good account of myself.
"I suppose Sean (O'Brien) and Cian (Healy) are two huge losses for any squad.
"But we've still got some fantastic ball-players in our side."