Cameron Smith blitzed Harbour Town Golf Links for a nine-under par 62 on Thursday to grab a one-stroke lead in the RBC Heritage over former British Open champion Stewart Cink.
Smith defied difficult afternoon winds to fire nine birdies, matching Cink at eight-under when he holed out from a bunker at the 17th and seizing the solo lead with a four and a half-foot birdie putt at 18.
"Everything just came together," Smith, chasing a third US PGA Tour title, said. "It was a great day on the green. I was hitting my irons really good.
"I had lots of good looks, and I just took advantage of them."
Smith's five front-nine birdies included three in a row at four, five and six. After a birdie at the 12th he kept the momentum going with a solid up and down at the 13th and added a three-foot birdie at 15 before his closing brace.
He said after the pressure of Masters week last week, chipping on the Harbour Town layout in Hilton Head Island, South Carolina, was "almost like a breeze.
"I was so scared almost last week on every chip shot, and I feel like I can be really aggressive around here," said Smith, who tied for 10th at the Masters won by Hideki Matsuyama.
Cink, who turns 48 next month, enjoyed "a very smooth round" after a disastrous start at the 10th, where he said his tee ball into the lake "was probably one of the worst opening drives I ever hit in my life.
"You'd think that's a bad way to start, but in a way it's a wake-up call," said Cink, who was feeling a Masters hangover in a different way.
"After playing in the Masters and being super-focused and intense, to come here and be lazy on the first shot was kind of like a slap in the face and it got my attention.
"And so we were really good and clean the rest of the way, and no more mistakes," said Cink, who had seven birdies and an eagle to position himself for a run at a third Harbour Town title to go with victories in 2000 and 2004.
Cink was two strokes clear of England's Matt Wallace and American Collin Morikawa on 65. Wallace had six birdies in his six-under effort while Morikawa, gearing up for the defence of his PGA Championship title next month, had seven birdies and a bogey.
Americans Charles Howell, Billy Horschel and Harold Varner shared fifth on five-under 66.
Will Zalatoris, who finished runner-up to Matsuyama at Augusta National by one stroke, carded a three-under 68.
World number one Dustin Johnson, coming off a missed cut at Augusta National in his defence of his Masters title, said he played better than his one-under 70 showed, although a three-putt bogey and a double-bogey on the par-three fourth were lowlights.
"I need to just clean it up a little bit tomorrow," Johnson said.
Leading first-round scores on Thursday in the PGA Tour RBC Heritage at Harbour Town Golf Links in Hilton Head Island, South Carolina (USA unless noted, par-71):
62 - Cameron Smith (AUS)
63 - Stewart Cink
65 - Matt Wallace (ENG), Collin Morikawa
66 - Charles Howell, Billy Horschel, Harold Varner
67 - Tom Hoge, Lucas Glover, Austin Cook, Kevin Streelman, Daniel Berger, Mackenzie Hughes (CAN), Corey Conners (CAN), Brian Harman, Lee Kyoung-hoon (KOR)