Johannesburg: Birdie bonanzas lifted South Africans Martin Maritz and Tyrone Mordt to the top of the leaderboard on 62 after the first round of the Joburg Open.
They claimed nine each and neither dropped a shot as the last of four tournaments on the South African leg of the Road to Dubai circuit began in pleasant, partly cloudy conditions.
Branden Grace carded a 63 and fellow South African Thomas Aiken and Frenchman Alexandre Kaleka a 64 each on a day when the par-71 Royal Johannesburg and Kensington east and west courses took a pounding.
Then comes a traffic jam with eight golfers shooting 65, 13 carding a 66 and 12 returning a 67 ahead of a weekend when thunderstorms threaten to disrupt play.
Defending champion and title favourite Charl Schwartzel of South Africa had to settle for a three-under 68 while a triple-birdie finish salvaged a 70 for Darren Clarke of Nothern Ireland whose erratic round included a double bogey.
Maritz, playing the longer, more demanding east course late in the day, collected four birdies on his outward nine and another five coming back, including four in a row.
Mordt had halves of 31 on the west course with five birdies picked up by the turn and the rest came in a four-hole blitz in the 1.3-million-euro tournament, the richest of the co-sanctioned events in South Africa.
"It was magical for me today and I am just over the moon," Maritz said after a round in which he found all but one green in regulation and his tee shot dropped on 10 of 14 fairways.
"A lot of the birdies I made today were either two putts or me hitting my approach shot very close to the pin," said the 33-year-old native of Pretoria now based in the American state of Oklahoma.
His 62 was an east-course record but will not be recognised as there was placing owing to the course in a north-east suburb of the South African financial capital being soaked by weeks of torrential rain.
Mordt, a nephew of former South Africa rugby union wing Ray Mordt, hailed his putting after an unexpectedly good start in pursuit of a maiden European Tour triumph.
"My putter got hot on the back nine. I did not always hit the ball that well but holed four long putts in a row on the inward half and that helped me a lot," he said.