Chase Koepka threatened to emerge from his overachieving brother’s considerable shadow as he grabbed the lead halfway through the opening round of the SA Open on Thursday.

Koepka‚ younger brother of US Open champion Brooks‚ shot a seven under par 65 to hold a one-shot lead over England’s Chris Paisley and a two-shot advantage over Scotland’s Bradley Neil.

Koepka‚ whose best result last year was tied fifth in the Zurich Classic in New Orleans‚ made an eventful start bogeying the first before recording an eagle on the second.

South Africa’s Garrick Higgo‚ Jacques Blaauw‚ Kyle McClatchie and Ulrich van den Berg all carded 68.

Local favourite and tournament host Ernie Els opened with a solid‚ if unspectacular 71. He admitted to feeling a little rusty.

“I was a bit out of sorts at the start‚” said Els.

“Then I started to get some good rhythm. I hit some good shots. 71 is what it is. It should be better.

"My putting feels really good but I missed quite a few birdie opportunities.

“All in all after the start I’ve got to take 71 and be happy with it‚” said the five-time champion.

As he approached the turn 2016 champion Brandon Stone’s round took a turn for the worse.

Three missed fairways saw him lose ground to his playing partners Dylan Frittelli and Andy Sullivan.

He missed the fairway to the right with his tee shot on the seventh.

He couldn’t reach the green in two and suffered the further indignity of watching his chip to the elevated putting surface roll back towards him down the slope.

He had to settle for a double bogey six to go two over.

The right side fairway bunker sucked his ball in on the following hole and although he got decent distance on his second he ended up next to a tree still shy of the green.

He found the green side bunker with his third as the ball failed to lob out favourably as he clipped the lip.

Stone signed for a bogey‚ before another errant tee shot on the ninth further slammed on the brakes on his round.