The 28-year-old did most of his good work early on in rounds in last week’s MyGolfLife Open in Hartbeespoort, where he tied for 28th behind Spaniard Pablo Larrazbal.
“It was steady golf,” said Forrest, who landed his maiden win on the circuit on home soil in the Hero Open at Fairmont St Andrews last summer.
“I got it going the first three days by getting it to three or four-under, but just didn’t finish off those rounds how I wanted.
“I then didn’t feel well at all on Sunday morning, which happens when you are in a different country, so it was a case of trying to get round in a couple under or so. “All in all, it was an okay week, but I left quite a lot out there.”
Forrest is among seven Scots teeing up in Johannesburg, joining Stephen Gallacher, David Law, Ewen Ferguson, Connor Syme, David Drysdale and Craig Howie.
Richie Ramsay had also due to be playing, but a back injury has forced the Aberdonian to pull out on the eve of the tournament.
“I’ve heard good things, so looking forward to it,” said Forrest of another new test. “It’s just nice to play in some warm weather, which it’s not been at home for a while.”
On the PGA Tour, Russell Knox and Martin Laird are both the the field for the Valspar Championship in Tampa.