Ireland captain backs debutant Jamie Osborne to survive Loftus baptism of fire

There had been an expectation that Jimmy O'Brien would be slotted into the side at fullback in Hugo Keenan's absence, but head coach Andy Farrell has instead made something of a surprise selection with Osborne, who primarily plays at centre.

The Leinster 22-year-old may have started at fullback only twice for his province, but O'Mahony has backed Osborne to rise to the challenge against the world champions at Loftus Versfeld.

"He has been very patient. The kid is pretty understanding and obviously has delivered incredibly well for Leinster over the last however many seasons," O'Mahony said at a press conference.

"One of the lads presented him with his (Ireland) jersey last night and he said it was not as if it was when the cap was going to come for him.

"He is one of these guys who is just really cool, calm, who wants to learn.

"He is a top-class professional at an early age, so you (media) said people were shocked, but I don't think anyone in our squad was shocked about it."

O'Mahony added: "Jamie has been in (the squad) a few times now and spent a lot of time with us. It just makes you more familiar with guys, more comfortable.

"You play for someone more when you know them better and he has been around long enough now to know us well enough for it to really matter to him.

"Playing for the group alongside you means a huge amount, and I am sure he will have had a great feeling of support from us over the last few days, certainly, and also since he has come into camp."

O'Mahony is set to win his 106th Ireland cap on Saturday, but it will be the first time he will have faced the Springboks in a Test match on their home soil.

"I think it helps you have been in the stadium before, but international rugby is different to (playing there in the) URC (United Rugby Championship)," the Munster back-rower said.

"It is a different animal, a different intensity, and you are going to have a different type of crowd.

"It is a big occasion for South Africa coming back here for the first time in a Test match since winning the World Cup, so I imagine it is going to be an incredible atmosphere for everyone."

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