NEW ORLEANS, Louisiana, April 26, 2012 (AFP) - Duke and Tringale both shot seven-under 65 on the par-72 TPC Louisiana course.
Tringale surged to his share of the lead with birdies at the last four holes, recovering from his early bogey at the par-three third with eight birdies overall.
"When I had chances to make birdies I was making them and made a couple 20-footers as well," Tringale said. "So, turned into a good day."
Duke, who like Tringale is seeking a first career US PGA Tour victory, had seven birdies, including three in a row from the fifth. He had two more at 11 and 12, and capped his round with a birdie at 18.
"The greens were good. Weren't too fast," said Duke, who has spent the past two seasons toiling on the Nationwide developmental tour. "You can't have them too fast here because of the wind and it will really will smack you. They're receptive. The course is in good shape, great shape."
The leading duo were one stroke in front of South African Ernie Els, Sweden's Daniel Chopra and Americans Steve Stricker and Chris Stroud.
Els made a birdie from a bunker at 18 to cap his 66.
"It was a tough day," Els said. "Good start and just kept at it."
Stricker started on the 10th tee and after his only bogey of the day, at the par-five 18th, played his last nine holes in five-under.
It was another shot back to Ben Curtis, John Rollins and Jason Dufner on 67. Former British Open champion Curtis arrived in Louisiana fresh from victory in the Texas Open on Sunday, his first tour title since 2006.
Watson had four birdies and three bogeys in his 71. He admitted he was "mentally exhausted" in the wake of his first major title at Augusta National earlier this month.
"I'm very exhausted, tough trying to play golf today," said Watson, who took a fortnight off after the Masters.
"I knew I needed to be here being the defending champ for the local fans. So I'm here, but mentally I'm not here."
He teed off on 10 and was two-over through seven holes. He held on, however, and finished his round with three bogeys and four birdies.
"Very happy with my score today," Watson later said via Twitter. "To shoot under par was awesome!"
England's Luke Donald, ranked second in the world, signed for a 73.
Leading first-round scores here on Thursday in the US PGA Tour's $6.4 million Zurich Classic of New Orleans (USA unless noted, par-72):
65 - Ken Duke, Cameron Tringale
66 - Daniel Chopra (SWE), Steve Stricker, Ernie Els (RSA), Chris Stroud
67 - Ben Curtis, John Rollins, Jason Dufner
68 - David Hearn (CAN), Webb Simpson, Graham DeLaet (CAN), Daniel Summerhays, Jonas Blixt (SWE)
69 - Briny Baird, Tim Herron, Graeme McDowell (NIR), Camilo Villegas (COL), Bob Estes, Kevin Streelman, J.J. Henry, Kyle Reifers, Miguel Angel Carballo (ARG), Kris Blanks, Vaughn Taylor, Charley Hoffman, Scott Verplank, Stuart Appleby (AUS), Russell Knox (SCO), Mark Anderson, Erik Compton, Troy Kelly