Ken Duke and Cameron Tringale topped the Zurich Classic leaderboard at 7-under 65 on Thursday, leaving defending champion Bubba Watson six strokes back at TPC Louisiana in his first tournament since winning the Masters.
Tringale birdied the final four holes and finished the round with eight birdies and a bogey. Duke had seven birdies in a bogey-free round. Both players are winless on the PGA Tour.
Steve Stricker, Ernie Els, Daniel Chopra and Chris Stroud were a stroke back at 66. Ben Curtis, the Texas Open winner Sunday in San Antonio, was another shot behind along with John Rollins and Jason Dufner.
Webb Simpson, a playoff loser last year in the event, had a 68.
Watson had four birdies and three bogeys in his 71.
Admitting to fatigue, Watson, playing the back nine first, was 2 over through the first seven holes. He birdied the par-5 18th and followed with three more birdies and a bogey on the front nine.
Second-ranked Luke Donald opened with a 73.
Tringale, coming off eighth-place finishes in the Houston Open and Texas Open, made the turn at 2 under and had a 5-under 31 on the back nine, highlighted by a 25-foot birdie putt on the par-4 15th and a 20-footer on the difficult par-3 17th.
Duke, attempting to make the most of his opportunity after a two-year exile on the Nationwide Tour, made three consecutive birdies on the front nine to make the turn at 3 under and birdied the par-5 11th and par-4 12th to get it to 5 under. He added birdies on the par-4 16th and par-5 18th.
Chopra, a two-time tour winner who has failed to make a cut this season, put himself in position to regain full-time status. He had failed to shoot in the 60s this year, a string of 15 rounds.