Ernie Els and Louis Oosthuizen were five off the pace set by James Hahn and Ricky Barnes after the first round of the AT&T Byron Nelson.
Hahn and Barnes take a two-shot lead into the second round after the pair shot 64s around the par 70 track. Both were equally impressive on Thursday, with Hahn going bogey-free, while Barnes dropped two shots, but made five birdies on the front nine to equal the day’s best round.
USA Ryder Cup star Matt Kuchar leads four players on -4, with world number one Dustin Johnson in the bunch on -3 and a share of 7th place.
Jordan Spieth is well-placed on -2 after the opening round as he looks to bounce back and return to the winner’s circle in his native Texas.
Louis Oosthuizen, who finished second last week, made two bogeys and birdied the last to make sure he finished Thursday in red figures. Also on that mark of -1 is veteran campaigner Ernie Els.
The Big Easy went out in 37 (+2), but produced some fireworks coming in to boost his confidence ahead of Friday’s second round.
Els made birdie at 10, at the par 3 13th, dropped a shot on 14, before finishing with two birdies and a par to be smiling at the end of a roller-coaster round.
Els wasn’t the only South African to experience golf’s ups and downs in a single round, as Charl Schwartzel found himself +3 after four before turning at that mark with no birdies in his outward nine.
Schwartzel got one back on 10, but a double on 11 saw him lose even more ground on the field.
Four birdies in his next six holes and he was level for the day, and that’s where he would end on a day where the big names struggled to stamp their authority on the field.
Rory Sabbatini laboured to a 75, while Tyrone Van Aswegen was +2 on Thursday, one better than defending champ Sergio Garcia.
