Osborne has big boots to fill with first-choice Hugo Keenan – who is preparing for the Olympics with Ireland’s sevens team – having starred under Farrell in recent years.
The debutant, who has started just two games for Leinster at full-back, will be tested at altitude at Loftus Versfeld Stadium on Saturday, with South Africa possessing some world-class kickers.
But Farrell is clearly confident in Osborne as he reeled off the player’s attributes.
“His skillset is very interesting for us to see, how we use the skillset that he’s got,” added the Englishman.
“He’s obviously going to add to our performance. From what I’ve seen lately in the back end of the URC [United Rugby Championship] season is that whenever he plays, he’s got presence, it doesn’t matter what position he plays.
“He suits the way we play, he’s bright, he gets himself on the ball a lot in an organising way. His communication is good and he’s accurate. He’s obviously got nice, soft hands and can play that way but also he can hit a line as well.
“To add to that, he’s deceptively very quick, good in the air, very athletic and he’s got a big left boot on him as well.”