Max Homa overcame a shaky start to Moving Day to take charge of the Nedbank Golf Challenge heading into the final round at Gary Player Country Club.
The World Number Eight hit a provisional ball on the second after a wayward drive and, although he found his initial effort, had to get up and down to save par.
He was unable to repeat the trick two holes later, where a bogey on the par three saw the halfway joint leader make his first Saturday move in the wrong direction.
However, the American responded with a birdie from six feet at the fifth before holing a spectacular bunker shot for eagle at the tenth.
A further gain on the par-five 14th saw Homa complete a three under 69 to lead by one on 13 under.
Matthieu Pavon, who shared the halfway lead with Homa, remains his nearest challenger after the Frenchman signed for a 70 to lie one back.
“I wasn't swinging it so well to start, I was a bit scrappy,” said Homa. “I hit the ball really well coming down the last nine or ten holes, that was nice. I didn't hole anything putting wise but I made a nice bunker shot for eagle on ten which helped because I couldn't get the ball to go into the hole. I hit it really well and had a lot of looks.”
On his eagle, Homa added: “It was one of those feeder bunker shots: if you land it short it's going to run, if you land it long it will spin. So I took a 56 and just played a low skidding one and it came off really good. It was one of the fun ones where 12 feet out you don't know how it could miss so those are the ones you like to have.”
Homa has won six times on the US PGA Tour but is keen to secure his first overseas victory on Sunday.
“It would be tremendous,” he said. “Every day we walk up nine and they have the plaques of everyone who's won and the names are stout so it would be amazing to add my name to the tradition here.
“I woke up a little homesick today and we always say if I'm going to be away from the family I might as well play good so it's been nice to stay true to that.”
Pavon led after mixing five birdies and a single bogey over his first 14 holes, but dropped shots at the 15th and 16th.
“All in all I'm pretty happy to score under par,” Pavon said. “In the heat and intensity you drain a lot of energy which probably got me in the end.”
Danish pair Nicolai Højgaard and Thorbjørn Olesen are tied for third on 11 under, with England's Dan Bradbury a shot further back in fifth.
