Bryce Molder benefited from an early delay in the Dean & Deluca Invitational as a blistering back nine lifted the American into a one-shot lead on the opening day at Colonial Country Club.
The 37-year-old from Arkansas was in the first group to tee off at the 10th under murky skies at Fort Worth but managed to remain level for his round after six holes before an hour and a half weather delay.
When play resumed, Molder exploded into life at the turn with back-to-back birdies before picking up shots on each of his last four holes as he carded 29 on the back nine to finish six under par.
Molder told the PGA Tour’s official website: “If you would have said, ‘I’m going to turn and shoot 29 on the back,‘ I’d have been like, ‘Are you sure you’re talking to the right person?’
“But that’s the way it happened. It all of a sudden comes together at the right time.”
Molder, whose only PGA Tour win came when he defeated Briny Baird to lift the Frys.com Open in 2011, has history for playing well on the course, having carded 62 on his first appearance in 2010 and then a 64 two years later.
He added: “I’ve always loved these greens so I got some good looks late and they happened to go in.”
American pair Patrick Reed and Webb Simpson also made six birdies but they both bogeyed the 247-yard par-three fourth and are in a tie for second alongside India's Anirban Lahiri.
Jason Dufner, the 2013 US PGA champion, joins fellow Americans Ryan Palmer, Kyle Reifers and Martin Piller a shot further back.
World number two Jordan Spieth, looking for his first win since January, started superbly with birdies on his first two holes although he was forced to settle for a three under 67 after picking up just one shot on the back nine.