The five changes made to Ireland's side will not weaken them as they take on the wounded Springboks, according to former international Alan Quinlan.
Ireland stunned South Africa to pull off a historic 26-20 victory in the first Test in Cape Town on Saturday, despite being down to 14 men for 57 minutes.
Sky Sports commentator Quinlan expects South Africa be a tough proposition in the second Test in Johannesburg but feels the new faces brought into the Ireland starting line-up by coach Joe Schmidt will stand firm.
"They are all good players who have come in and replaced the guys that started last week in that brilliant win in Cape Town," said Quinlan.
"The big talking points are Quinn Roux and Stuart Olding - they're two guys who maybe weren't expected to start.
"Joe Schmidt is a fan of Quinn Roux who hasn't played a lot of rugby this year but he's said that he brings a lot of value in the set-piece and physicality that they're going to expect from the Springboks this week.
"Stuart Olding is a very talented player who has had a good season with Ulster - again Joe Schmidt compared him to a former great in Gordon D'Arcy so I don't think the changes are going to affect the team, in fact they might boost the team.
"The players are fresher, it's going to be physical again like it was last week in Cape Town.
"It's going to be very difficult - they made history last Saturday in Cape Town and it was an incredible performance considering they had 14 men for most of the game."
Ireland are expecting a Springbok backlash. "They're wounded, there's no doubt about that," he said. "They're definitely going to come out and try to impose themselves.
"The Springboks made a lot of errors, as good as Ireland's performance was, South Africa were poor in their execution. They haven't had a lot of time together so they're expecting to be better and (South Africa coach) Allister Coetzee said that."
Tighthead prop Tadhg Furlong, back row Rhys Ruddock and left wing Craig Gilroy are the other additions to the starting lineup.