Martin Maritz and Tyrone Mordt share the first round lead at the Joburg Open after both carded faultless nine under par rounds of 62.
However, they came on different courses at the Royal Johannesburg & Kensington Golf Club, and while Mordt's efforts on the West Course were outstanding, Maritz's on the more difficult East Course were truly sensational.
The two South Africans registered nine birdies each, with Maritz's effort coming on the longer East Course which provided only four of the top 26 players on day one.
They lead by a shot from compatriot Branden Grace, following his 63 early in the day.
This week's co-sanctioned European and Sunshine Tour event is being played over two courses on the first two days, before the cut is made and the final two rounds are played on the testing East lay-out.
Another local, Thomas Aiken, also excelled on the East after his 64 put him a on seven under and left him as the only other player in the top ten to have gotten the more difficult 18 out of the way.
Also on that score was Frenchman Alexandre Kaleka, while eight players were a further stroke back on six under after 65s.
Among them were Britons Stuart Manley, Jamie Elson and Robert Dinwiddie along with Norway's Marius Thorp, Dutchman Floris de Vries and South African trio Peter-Henric McIntyre, Garth Mulroy and Divan van den Heever.
The man they were all chasing was Maritz, who has never won a Tour event and who recently took a break from professional golf due to frustration over his game.
The 33 year old begin with successive birdies, picked up further shots at the sixth and eighth and then concluded with five birdies in his last six holes.
Amongst the highlights of that run were a 15 footer at the 15th and his tee shot at the par three next, which spun to within a foot of the hole.
Maritz admitted that despite suggestions the West Course was easier, he felt otherwise.
He said: "That's what everybody thinks, but over the last few years, I think I've played better on the East Course.
"I think it's because in junior days and amateur days we played a lot of tournaments on that course.
"I think if I can shoot anything close to that tomorrow, I'll be very, very happy."
The Pretoria-born golfer, now based in Tulsa, Oklahoma where he had taken up a club pro role in his time away, added: "I've been working really hard on my short game, it's not my strong point, so I'm just ecstatic, it's just a magical round for me today and I'm over the moon."
Mordt also made a birdie-birdie start on the way to turning in a five under par 31, before collecting four more gains on the back nine.
"My putter got hot on the back nine," he said. "I didn't necessarily hit it that well, but I just holed four long putts in a row, and that helped me out a lot."
Countryman Grace, the clubhouse leader for most of the day, recorded six birdies and an eagle in his round, and conceded that the West Course players had no option but to score low today.
"I thought beforehand that one of the keys was to go low on the west and fortunately I managed to do it today," he said.
"I played really well, I didn't make any mistakes out there and everything went to plan, so I'm pretty pleased with that."
Defending champion Charl Schwartzel had a solid start to the tournament with a 68 on the East Course he birdied the 11th from 12 feet and spun his approach at the 13th to three feet.
One of his playing partners, Northern Irishman Darren Clarke, ended on one under 70 thanks to three successive birdies to finish.