World number 30 Grace, the highest ranked player in the field, scored all his eagles on par-five holes and secured his third with an excellent 20-foot putt on the 15th hole.
Koepka set the mark in the morning wave with a round that included seven birdies and an eagle against two dropped shots while Grace's rollercoaster score came in the afternoon. Obviously a little bit rusty with some of the wedge shots and things like that but all in all very pleased with the outcome and I think I pretty much got the most out of that round.
The fact that he became the first South African to register three eagles in a round on the European Tour showed just how long and straight he was off the tee and how good his putting was as he also collected three birdies.
Most of the golfers interviewed before the start of the South African Open agreed that the Glendower Golf Club course would demand good driving and putting in order to excel, and Branden Grace epitomised that as he fired a fantastic seven-under-par 65 to claim a share of the first-round lead on Thursday. "On all the par-fives, I hit great tee shots".
'I can't remember when, or if, I've ever made three eagles in a round but it was fun, ' said Grace, who eagled the second, eighth and 15th, all of them par fives.
United States manufacturing surges in December, ISM shows
The Employment Index declined 2.7 points to 57.0 in December, indicating expansion for the fifteenth consecutive month. The group's New Orders Index came in at 69.4%, the highest since January 2004 when the index registered 70.6%.
The pair had a one-stroke edge over Chris Paisley of England and two over Bradley Neil of Scotland, South Africa's Erik van Rooyen and Richard Sterne, and Spain's Nacho Elvira. I drove it really well, which gave me a chance to get it close'. The only one I was really aggressive with was the second hole.
He said that putt had given him confidence for the rest of the round despite struggling with his speed control. It was just the second hole of the day, and I had something like 244 to the flag into the wind.
"Inside 150 yards, I was really good today", he said.
Paisley, who is seeking his first European Tour title, said: 'I'm really happy coming off five weeks off. So, it was a big deal to start off my round, you don't want to make double on the opening hole.
Tournament host Ernie Els carded an opening 71, while Retief Goosen was on three-under 69, together with Charl Schwartzel who had a frustrating day with three bogeys in his round. I definitely left a lot of shots out there today, so hopefully I can keep up this kind of play.