Richard Sterne and Maximilian Kieffer both fired 8-under 63s on Thursday to grab a share of the lead after one round of the Joburg Open.
Sterne, a runner-up at the Dubai Desert Classic last week, and Kieffer both played the par-71 West Course at Royal Johannesburg and Kensington Golf Club.
Bryce Easton had a hole-in-one at the more challenging, par-72 East Course en route to a 7-under 65. The South African sits alone in third place.
Trevor Fisher, Jr., Tyrone Mordt, Peter Uihlein, Tyrone Ferreira, Jake Redman, Joakim Lagergren, Allan Versfeld and MJ Daffue share fourth at 6-under.
Masters champion Charl Schwartzel, who won this event in 2010 and 2011, teed off on the East Course and ended at 4-under 68. Branden Grace also played the East Course, but the South African will likely have to improve on his level par 72 in order to successfully defend his Joburg Open title.
Sterne started strong in Dubai as well, where he tallied a 62 on the first day. The five-time European Tour winner nearly matched that feat on Thursday when he turned in six birdies and a chip-in eagle at the par-5 ninth.
"Some days it feels good and everything kind of happens," said Sterne, who won this tournament in 2008. "Golf is strange -- you've got to hit the right kind of shots at the right time. I hit 17 greens today, so I was never really in trouble at all."
Kieffer is looking for his first European Tour win after a strong start to his rookie campaign. The Challenge Tour graduate tied for 17th in Dubai after ending tied fourth in Durban at the season-opening Nelson Mandela Championship in December.
"When you come from the Challenge Tour everyone says that you have enough to play out here, but you still want to prove it," admitted Kieffer, who carded eight birdies during his bogey-free opening round. "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."
After Sterne and Kieffer found the clubhouse, another rookie, Espen Kofstad joined the co-leaders at 8-under through 16 holes. But the Norwegian stumbled to a triple-bogey on the last to drop to minus-5.
The 210-man field will split courses again on Friday before the tournament moves to the tougher East Course for the final two rounds. Sterne, though, appeared optimistic about the change in scenery.
"I had three good rounds around the East Course (in 2008)," said Sterne. "If I can do that now I'll have a chance on Sunday."
NOTES: Kieffer won the Gujarat Kensville Challenge on the Challenge Tour in 2012 ... This tournament is co-sanctioned by the European Tour and Sunshine Tour of South Africa ... Last year, Grace took a 3-shot lead into the final round and fired an even-par 72 to hold off Jamie Elson by one stroke. Grace went on to win three more times in 2012 for a European Tour-high four victories on the season.