Improved putting enabled major winner Louis Oosthuizen to take a one-shot lead in the South African Open on Saturday after carding a seven-birdie 64 in the third round.
The South African, who won the British Open in the 2010, takes a 15-under total of 198 into the final round of the European Tour event at Randpark Golf Club in Johannesburg.
Oosthuizen, the defending champion and pre-tournament favourite, leads from Marcus Armitage of England, whose 62 was the best round of the day, and is two shots ahead of fellow South African Jaco Ahlers, who shot a 68.
"I spent time on the putting green after the second round and it paid off," said Oosthuizen who is ranked 20th in the world.
"My second round putting was not great, but I got my line, speed and rhythm back today and it is reflected in my score.
"Birdies on two, three and four set me up nicely on a course where I feel very comfortable. The cool, calm conditions were perfect for golf.
"Ahead of the third round I felt the need for at least a four-under round and it was fantastic to better that minimum target by three strokes.
"It would mean the world to me to win this championship two years in a row," added Oosthuizen who is seeking to emulate 2003 and 2004 champion Trevor Immelman.
After a disappointing second-round 72, Armitage surged back into contention for a first European Tour victory by equalling the lowest score of the week.
The Englishman belied his 1,398 world ranking with two eagles and six birdies and his only blemish came at the par-four final hole, which he bogeyed.
"I could spend days just chipping and putting and that aspect of my game came to the fore today," said Armitage.
Those trailing Oosthuizen by three shots include 18-year-old South African Jayden Schaper, whose 69 kept him in contention to become the first amateur in 61 years to win the event.
Overnight leader Tapio Pulkkanen of Finland, who wears a trilby hat rather than a traditional cap, bogeyed four holes in a round of 72 and lies five shots off the pace.
Major winner Louis Oosthuizen takes a one-shot lead into the final round of the South African Open