American David Lipsky took a one-shot lead into the weekend at eight under but the Saltire was flying high at Leopard Creek Country Club, with Warren and Scott Jamieson just a shot back and David Drsydale and Doug McGuigan at six under.
Warren is a three-time winner on the European Tour and while he was delighted to see his countrymen doing well, he was even more pleased to be challenging again himself after a 67.
“I’ve seen the Scots up there,” he said. “Scott Jamieson is a good friend, I see he finished strong as well, and Doug McGuigan, so it’s nice to see and hopefully we keep the momentum for the weekend.”
He added: “I think I learned a lot that week (at Qualifying School), thought it was going to be a long week so I kind of surprised myself.
“I felt like I just played golf, purely. I just played the shots I felt I could play. I felt like I was playing golf again as opposed to playing golf swing so I’m just trying to take that approach into the new season.”
Jamieson has a good record in South Africa, winning the Nelson Mandela Championship presented by ISPS HANDA in the season 2013 and finishing in the top three here just a week later.
He recorded another top five here last time out and was delighted to be performing well again after birdieing five of his last six holes.
“This is a very special place,” he said. “I’ve had some good finishes, not just here but in this country in general. Maybe half of my career money has come out of South Africa so I always try and make a point to come down here because I seem to enjoy it.
“Feeling good to be in the mix tomorrow.”
McGuigan made seven birdies on the back nine as he recorded the lowest nine-hole score to par of the season.
His best European Tour finish came when he lost a play-off at this event almost 16 years ago and the 48 year old - an eight-time Sunshine Tour winner - was delighted to be in contention.
“It’s exciting to be in the mix here again,” he said. “I lost this event in a play-off and it’s been a thorn in my flesh for many years. I began to wonder if I’d ever get back in the mix but I played nicely today. I look forward to the weekend and whatever happens, happens.
“On the back nine I got things going. I had nine one-putts on the back nine which I don’t think I’ve ever done that before.”
Drysdale had to withdraw from last week's South African Open hosted by the City of Johannesburg with an arm injury but is showing no ill-effects after back-to-back rounds of 69.
“The game feels great ball-striking-wise, tee to green I’ve been solid the first two days,” he said. “This is a golf course I love, a golf tournament I love coming back to so everything feels great. I stay on site, here on the river, just a relaxed time and I really, really enjoy this week.”
He added: “When I came down number nine, I saw the Saltires lying second, third and fourth and that was nice to see. So there are four of us up there and hopefully we can kick on at the weekend.”