American Johannes Veerman shot a bogey-free, nine-under-par 62 to take the first-round lead at the South African Open in Johannesburg.
Veerman carded nine birdies, seven of which came on the back nine, to claim a one-stroke advantage over South Africa's JC Ritchie and Italian Nino Bertasio at Randpark Golf Club.
Home favourite Branden Grace was one shot further back, in a group of six players on seven under which included two more South Africans in Toto Thimba Jnr and Rourke Van Der Spuy.
Chilean Matias Calderon, England's Sam Horsfield and Greek Peter Karmis also shot 64s.
Gavin Moynihan is the best of the Irish following the opening round following a three-under 68 to leave the Dublin in a tie for 47th place.
Jonathan Caldwell hit a one-under 70 to open, while Conor Purcell posted a level-par 70. Both players have work to do in the second round to make it through to the weekend as they currently sit tied 96th and tied 138th respectively.
Veerman's round on the Bushwillow Course - one of two courses being used in the event - was his lowest on the European Tour and continued a remarkable run that began at Qualifying School last autumn.
The 27-year-old looked like missing out on a card when he sat five over after two rounds but then scores of 67, 67, 66 and 66 saw him claim a place on tour. He has since secured two top-10 finishes in three events.
Veerman told europeantour.com: "I've been practising really hard over the last six or seven months and I've been getting better. To come out and start 2020 playing like this gives me a lot of confidence.
"It is only the first round but it is a step in the correct direction."
Veerman played a steady opening nine with birdies at the second and fifth before bursting into life with three more in succession from the 10th.
That took him into a share of the lead and he then moved clear by birdying his last four holes.
Bertasio drew level with an eagle on the 17th but then a poor tee shot led to a bogey at the last. Ritchie also played bogey free and finished strongly with birdies on the 17th and 18th.
Grace's 64 was the lowest round of the day on the Firethorn Course.
