Bubba Watson and Matt Jones share a one-shot lead after the opening round of the Classic of New Orleans.
America's Watson carded six birdies and an eagle to shoot a 66 that was matched by Jones when the Australian chipped in from 57 feet to birdie the last.
Six players, including Sweden's Carl Pettersson, are on five under par.
Englishman Luke Donald is two shots back on four under while Northern Ireland's Graeme McDowell is one over, and England's Justin Rose five over.
Donald, who has a chance to become world number one for the third successive week if he wins the PGA Tour event, had a bogey-free opening round and fired himself into contention with a couple of birdies in his final two holes.
Jones, who began his round on the back nine, sank eight birdies, including a run of four in a row that began at the par-four 16th and narrowly missed out on a fifth at the second.
"I had a lip-out on two for birdie, which would have been nice," the Australian said.
"I had a lot of putts going in from distance. It was a nice change. It has been a while."
Watson, who won at Torrey Pines in January, holed a 32-foot putt on the 11th for his eagle after following his 343-yard drive with 237-yard six-iron to the green.
"It was downwind," he smiled, after admitting the Louisiana was not his favourite track to play.
"The way the course is, it just doesn't fit my eye. It's a great layout. For me, it's just not one that I want to play every day.
"But it just worked out. I hit my driver really well. I've been hitting it good all year, but I made some putts and hit some good iron shots and somehow came out six-under."