“When you come from the Challenge Tour everyone says that you have enough to play out here, but you still want to prove it,” said Kieffer.
“It’s a new world and you don’t really know what to expect, so I’m happy that it went pretty good so far.
“That round was great. I’ve been playing well the last few weeks and I just tried to stay positive on the golf course, and luckily today was another good round.”
He and Sterne were briefly joined on eight under by another rookie, Norwegian Espen Kofstad, but the 25 year old triple bogeyed the last to finish on five under.
South Africa’s Bryce Easton had a hole-in-one en route to posting an East Course-best 65, which gave him third place on seven under.
“It’s one of those things – you don’t think about it when you’re playing the hole, but when it goes in it takes a couple of seconds to realise that it’s actually disappeared,” said Easton.
Defending champion Branden Grace and two-time winner Charl Schwartzel were also on the East Course on day one, but while former Masters Tournament winner Schwartzel opened with a four under 68, Grace could only produce a level par 72.