The 37-year-old Glaswegian sits joint-13th, three shots off the lead, after signing for a two-under 70 that included an eagle-3 at the 18th - his ninth hole.
It was Jamieson’s seventh score in red figures in nine rounds on the European Tour’s three-event South African Swing and 14th in his last 17 rounds.
He said: “As the wind picked-up, the course got trickier while the ball wasn’t travelling all the far early on with it being overcast and that made it a lot cooler than what we are used to seeing down here.
“Also, the fairways are a little soft and, when you land in the fairways, your ball kind of stops dead so the course is long but thankfully, they moved-up a few tees.
“It is what it is and, much like last week, you have to stay patient and, if you get a chance, you have to try and grab it where you can.”
Home player Christiaan Bezuidenhout, winner of last week’s Alfred Dunhill Championship at Leopard Creek, is among six players tied for the lead on five-under.Alongside him are fellow South Africans Dean Burmester, Jacques Kruyswijk and Ruan Korb, as well as Austria’s Matthias Schwab and Italian Aron Zemmer.
David Law (71) and Connor Syme (72) are both sitting inside the top 50 but David Drysdale (76), Calum Hill (77) and Ryan Lumsden (78) all face a battle to make the cut.