The five-time champion was paired with his sister's son Jovan Rebula in round three and both enjoyed an excellent day, with Els carding a 68 and Rebula signing for a 70.
Els may have two Claret Jugs in his trophy cabinet but by winning The Amateur Championship this year, Rebula achieved something his uncle never managed, and they will both be hunting silverware on Sunday.
Els will enter day four six shots behind leader Louis Oosthuizen while at two shots further back, Rebula's focus is likely to be on the Freddie Tait trophy for leading amateur - a race he currently heads by three shots.
Regardless of what happens on Sunday, Saturday will live long in the memory of the Els clan.I’m happy he’s good enough. I hope he breaks every record I have - Ernie Els
“A special day,” said Els. “We took some pictures on the first tee from our phones to get it on record.
“I think as time goes on we will reflect on this day. I know I will know that this is pretty special. He is a youngster so it might not settle in yet with him but knowing the kid since he was in nappies and now playing the South African Open is special.
“It was great to see my sister out there, Dragan (brother-in-law) caddying for Jovan. As parents, they must be so proud and as an uncle, I’m just as proud.
“I’m happy he’s good enough. I hope he breaks every record I have. I only have love for Jovan and I just wish him all the best.”
Rebula added: “This must be one of the quickest rounds of golf I’ve ever played. I wished it could have carried on the whole day.
“For me, it was a dream to be able to play with my uncle one day. It doesn’t matter where it is but especially the South African Open, it’s an honour and I really enjoyed it out there. We had such a fun time.
“My uncle is one of my role models and it’s not necessarily just on the golf course, he’s just such a special person. He’s always caring for other people around him and that’s what I look up to more than the golf itself.
“But with my uncle’s records, it’s something really special and I would probably have to work really hard to achieve what he has.”