Keenan Davidse hit nine birdies to card a sensational 63 and take a one-shot lead after the opening round of the Joburg Open on Thursday.
The 28-year-old took advantage of playing the shorter Bushwillow course to finish eight-under, and his day could have been even better had he not bogeyed the par-three sixth.
Davidse had been in hospital for four days in the build-up top the event at the Randpark Golf Club but he shrugged off the flu to set the pace on home soil.
He was three-under by the time he reached the sixth, and after that dropped shot he never looked back, birdieing five of the back nine to reach the clubhouse in fine fettle.
"I'm obviously very happy," he said. "I've worked very hard. I went to Mauritius last week and didn't play too well. I was in hospital for about four days, so I'm very chuffed today.
"When I played the Sunshine Tour event at Simola my little boy was sick with a bad chest. Then my wife had flu and then I got flu and lost a lot of weight. I couldn't deal with that and the heat in Mauritius, so I checked myself into hospital for four days.
"I didn't really have any expectations coming into the week. I'm just out here to have fun, obviously, so I'm very blessed to be playing well.
"It's always nice leading a big tournament and especially the Joburg Open. I needed to play well today - it's a good feeling."
Behind him, a group of six players are well placed on -7 after they too flourished on the Bushwillow 18, Matthew Baldwin claiming two eagles in the hunt of Davidse.
He is joined by James Morrison, Sebastian Heisele and South African trio Jared Harvey, Erik Van Rooyen and Ockie Strydom.
The leading seven players will take to the Firethorn course on Friday hoping to maintain their form.
Six-under was the best any player who tackled the second course could manage, Dean Burmester one of another six to sign for a 66.
Things were not so good for defending champion Darren Fichardt, though, as he could only finish in 75, leaving him well adrift.