Otto hit seven birdies and an eagle to go 14 under at the Jack Nicklaus-designed Serengeti course. The South African, who grew up nearby in eastern Johannesburg, leads from a four-way tie for second made up of Goosen, Sweden’s Magnus Carlsson, Thomas Aiken and Garth Mulroy.
Goosen (71) couldn’t capitalize on a blistering start where he birdied his first three holes. He had bogeys at Nos. 9, 13, 17 and 18 for his worst round at the $1.3 million European Tour tournament this week.
Defending champion Els took a nine on the par-5 No. 16 after he hit his tee shot into the water and then his second drive into a bunker. He was on the green in six and three-putted and tumbled down to a tie for 53rd with his 4-over 76.
Carlsson carded a 6-under 66 to move to 11-under and break up a run of six South Africans in the top seven.
Aiken had a 4-under 68, spoilt only by a double-bogey on No. 9. Last weekend’s Alfred Dunhill Championship winner, Mulroy recovered from four bogeys in his front nine to make four of his six birdies on the way home.
Playing alongside Els, Otto bogeyed his first and then dropped another shot at No. 5. But he picked up eight shots from No. 7 to take him within reach of his second European Tour title and the first since the Italian Open in 2008.
“I haven’t won it yet. It’s a new day tomorrow,” said Otto, who has recently appeared calmer on the course after once throwing his clubs into a river during a tournament on the local Sunshine Tour.
“I’m not a guy who gets all nervous,” Otto said Saturday. “Maybe angry, not nervous.”
Goosen’s late slide came as a surprise after the two-time South African Open winner began sublimely on the pacey greens. He had five birdies overall, but four bogeys as well, including back-to-back dropped shots to finish.
His slip allowed Carlsson to play alongside Otto in Sunday’s final match, where the Swede will bid to become only the eighth non-African winner in 101 versions of the South African Open.
Carlsson also needs a top-two finish to retain his tour card for 2012.
“I’m not going to think about it (retaining his card),” Carlsson said. “I’m not going to make stupid decisions.”
England’s Richard Bland (66), Spaniard Alvaro Velasco (66), Austrians Markus Brier (67) and Bernd Wiesberger (70) and second-round leader Steven O’Hara of Scotland (74) were all five shots off the lead and in with a chance of a rare foreign win at the tournament.
Els’ disaster at No. 16 came after the five-time winner was twice forced to step away from his tee shot because of fans taking photos on their cell phones while he was lining up.
“They should ban the guys and get them to hand in their cell phones.” playing partner Otto said. “It gets to you.”