Matt Ford seized the outright lead at the Africa Open on Friday by one shot, but acknowledges there is still room for improvement.
The Englishman - who almost joined the postal service before making it through November's qualifying school - shared the overnight top spot with Ireland's Kevin Phelan, but delivered a round of 66 to post a score of 11-under for the tournament so far.
However, having registered a flawless opening round, Ford was left to rue bogeys on holes nine and 17 on Friday.
"I don't think you can ever get all of it out of the round," he said. "I missed a short one on 17 and hit a poor tee shot off nine, so those were a couple of mistakes, but you're always going to make a few of those.
"I would have taken 11-under at the beginning of the day."
Ford, who capitalised on beneficial weather conditions before strong wind set in, now holds a one-stroke lead over Spain's Eduardo De La Riva, who dropped two shots on his first three holes before surging back with seven birdies.
"I played a very good round with good golf and good putts," said De La Riva. "I am very happy with the first two rounds."
The tournament has not been won by a foreign player in its seven-year history.
Jaco van Zyl, Gregory Havret and Erik van Rooyen sit two shots further back, while Maximilian Kieffer is tied for sixth after posting a field-leading nine-under for the day.
Phelan, who had shared the lead with Ford overnight, failed to replicate that performance and slipped to 14th with a par round.
Top home player George Coetzee is among the highest profile players who look set to miss the cut.