Grace, who is ranked 30 in the world, shares first place at seven under with American Chase Koepka, a brother of reigning US Open champion Brooks, who lies 306 places lower on the merit ladder.
"I get on a streak like this where I make one of those longish putts in the first couple of holes, then I pretty much know I just have to get it there".
Paisley, seeking a first title on the tour, is 15 under-par for the tournament and leads home favourite Branden Grace (66).
Grace, a South African, had a haywire front nine that included two eagles, two birdies and two bogeys.
The Frenchman was in new territory when he shared the 36-hole lead, never before having been in the top five at halfway on the European Tour. "I'm just really excited about it".
Trump asked why 'pretty Korean lady' wasn't helping with North Korea negotiations
NBC News also cited a source saying Trump "frequently uses that kind of language", despite those around him telling him not to. In a tweet, Trump said: "The language used by me at the DACA meeting was tough , but this was not the language used".
Chris Paisley will take a narrow one-shot lead into the final day's play of the BMW SA Open as Branden Grace moved into second position with a blemish-free back nine. "I certainly hope that I can keep that trend (of Englishmen winning the SA Open) going". France's Saddier had the round of the day at Glendower Golf Club in Johannesburg, a blistering, course record-equaling 63 with an eagle, seven birdies and no bogeys.
"At the moment it's weird, I feel like I didn't play awesome".
South African major winners Ernie Els (71), Retief Goosen (69) and Charl Schwartzel (69) all had solid opening rounds, but Trevor Immelman (79) carded five bogeys and a double-bogey on a day to forget for the 2008 U.S. Masters champion.
Defending champion Graeme Storm of England, who pipped golf superstar Rory McIlroy of Northern Ireland in a play-off previous year to win the second oldest national championship after the British Open, carded a 75.
South Africa's Darren Fichardt is a shot further back after surging through the field with a brilliant 64 which featured eight birdies in the last 12 holes.