Luke Donald's quest to regain golf's world number one position got off to a poor start at the Zurich Classic.
Donald needs to finish in the top seven at the event in Avondale, Louisiana, if he is to reclaim top spot from Rory McIlroy - who does not return to action until next week's Wells Fargo Championship.
However, Donald could only manage an opening round of 73 - and at one over par the 34-year-old sits eight shots off the pace set by Ken Duke and Cameron Tringale.
Three birdies and three bogeys were followed by a five at the par-three 17th for Donald - although the Englishman got a shot back on the 18th.
Bubba Watson is also well off the pace after making his return to action following victory in The Masters.
Watson won this event last year but this time around he carded a steady opening round of 71, one under par.
The American had birdies on the second, sixth and seventh holes but bogeys on the eighth, 10th and 16th meant he needed a birdie on the 18th to finish the first round under par.
Duke had seven birdies in a bogey-free round, while Tringale - who is also seeking his first win on the PGA Tour - recovered well after a bogey on the third, finishing with four birdies.
South Africa's Ernie Els, Sweden's Daniel Chopra and United States duo Steve Stricker and Chris Stroud are a shot behind the leaders on six under, with fellow Americans Ben Curtis, John Rollins and Jason Dufner on five under.
Northern Ireland's Graeme McDowell and Scotland's Russell Knox are the best-placed Britons after the first round, on three under par.
England's Greg Owen was two under after the first round, with Brian Davis a shot further back alongside Watson. Justin Rose managed a level par opening round, while Gary Christian was on three over.
Collated first-round scores, Classic of New Orleans, TPC of Louisiana, Avondale, Louisiana, United States of America
(USA unless stated, par 72):
65 Ken Duke, Cameron Tringale
66 Steve Stricker, Chris Stroud, Daniel Chopra (Swe), Ernie Els (Rsa)
67 John Rollins, Jason Dufner, Ben Curtis
68 David Hearn (Can), Daniel Summerhays, Graham Delaet (Can), Jonas Blixt (Swe), Webb Simpson
69 Charley Hoffman, Vaughn Taylor, Bob Estes, Troy Kelly, Briny Baird, Stuart Appleby (Aus), Kris Blanks, Erik Compton, Tim Herron, Graeme McDowell (NIrl), Kevin Streelman, Mark Anderson, J J Henry, Miguel Angel Carballo (Arg), Kyle Reifers, Camilo Villegas (Col), Scott Verplank, Russell Knox (Sco)
70 Seung-yul Noh (Kor), Jason Kokrak, Garth Mulroy (Rsa), Colt Knost, Brian Gay, Greg Owen (Eng), Jimmy Walker, Stephen Ames (Can), Lucas Glover, Greg Chalmers (Aus), Michael Putnam, Brian Harman, William McGirt, Alex Cejka (Ger), George McNeill, Mathew Goggin (Aus)
71 Bud Cauley, John Peterson, Nick O'Hern (Aus), John Mallinger, Charles Howell III, Nathan Green (Aus), Hank Kuehne, Roland Thatcher, Rickie Fowler, Patrick Reed, Brian Davis (Eng), Rodney Pampling (Aus), Chris Di Marco, Bobby Gates, Bubba Watson, J.B. Holmes, Sung-hoon Kang (Kor), Jeff Maggert, K J Choi (Kor), Rocco Mediate
72 Jeff Overton, Edward Loar, Justin Rose (Eng), David Mathis, John Merrick, John Senden (Aus), Scott Piercy, Fred Funk, Alexandre Rocha (Bra), Chad Collins, Trevor Immelman (Rsa), Richard H. Lee, Troy Matteson, Patrick Sheehan, Spencer Levin, Marco Dawson, Bill Lunde, Ryan Palmer, David Toms, Chris Couch, David Duval, Matthew Jones (Aus), Brandt Jobe, Kevin Kisner, Michael Bradley, Gavin Coles (Aus), Will Claxton, Danny Lee (Nzl), Harris English, J.J Killeen, Matthew Every, Andres Romero (Arg), Carl Pettersson (Swe)
73 Brendon De Jonge, Jerry Kelly, Scott Dunlap, Retief Goosen (Rsa), Steve Flesch, James Driscoll, Tom Pernice Jnr., Blake Adams, John Daly, Keegan Bradley, Ted Potter, Jr., Cameron Beckman, Brendon Todd, Luke Donald (Eng), Tommy Gainey
74 Nick Watney, Chris Kirk, Scott Brown, Martin Flores, Steve Wheatcroft, Matt Bettencourt, Chez Reavie, Peter Hanson (Swe), Justin Leonard, Roberto Castro, Billy Horschel, Jason Bohn, Pat Perez, Billy Hurley III, Josh Teater, Tommy Biershenk
75 Joey Mclister, Ricky Barnes, Tim Petrovic, Gary Christian (Eng), Angel Cabrera (Arg)
76 Bryce Molder, D.A. Points, Stephen Gangluff, Hunter Haas, Geoff Ogilvy (Aus)
77 Ben Crane, Jake Narro, Joe Ogilvie, Phillip Hui, Ryuji Imada (Jpn), Steven Bowditch (Aus), Jamie Lovemark, Charlie Beljan
78 David Byrne (Can), D.J. Trahan, Derek Lamely
79 Robert Karlsson (Swe)
80 Scott Stallings, Kyle Thompson