Jordan Spieth's challenge at the Sony Open in Hawaii suffered a huge blow when he quadruple-bogeyed his penultimate hole in the opening round.
Spieth was well placed on four under after mixing seven birdies with three bogeys over 16 holes at Waialae Country Club, but he encountered severe tree trouble at the par-four eighth as he ended the day six shots behind leaders Zach Johnson and Chris Kirk.
The problems for the Open champion began when he pulled his drive left into the trees, and his second advanced barely 20 yards after his ball cannoned off an overhanging branch.
Spieth's next two shots also hit wood and stayed in the rough before he managed to gouge his fifth shot into a greenside bunker, from where he took three more to get down as he tumbled down the leaderboard to level par.
To his credit, Spieth did respond with his eighth birdie of the day at the ninth to return a 69, but it was his fellow Open champion Johnson who enjoyed the best scoring of the day along with Kirk in typically warm and blustery conditions.
Johnson opened with three consecutive birdies, and he converted a sublime pitch from six feet at the last to cap a flawless 63 which earned him a share of the clubhouse lead with Kirk, who had earlier birdied four of the last six holes and also kept a bogey off his card.
In-form Brian Harman, who was third at Kapalua last week, is among four Americans in a share of third on six under along with former Ryder Cup player Vaughn Taylor, while defending champion Justin Thomas opened with a solid three-birdie 67.
Thomas could not reach the heights of his sensational 59 on day one 12 months ago, but he kept a birdie off his card and was clearly at ease having Phil Mickelson's former long-time caddie Jim "Bones" Mackay on his bag with his regular caddie recovering from a foot problem.
But it was a tough day for former world No 1 Luke Donald as he carded three bogeys and a double-bogey at the 10th before a birdie at the last salvaged a two-over 72 which left him in a tie for 116th place and needing to go low on day two to avoid missing the cut.