American Gary Woodland rose out of the pack and grabbed a one-stroke lead after the first round of the US PGA Championship.
Woodland erased Rickie Fowler's early-morning lead which looked like it was going to hold up most of the morning, with a six-under-par 64 at Bellerive Country Club on Thursday.
The 34-year-old birdied seven of his last 11 holes to jump ahead of countryman Fowler in St Louis.
Still without a top-10 finish at a major, three-time PGA Tour champion Woodland has set himself up for a career-changing week.
Fowler – wearing yellow in tribute of Australian golfer Jarrod Lyle who passed away on Wednesday following an ongoing battle with cancer – took the early lead with a five-under 65.
He found his best form late, birdieing five of his last 11 holes. With the course playing soft early in the morning, Fowler was able to roll in four birdies on the tough front nine.
South African Brandon Stone, who enjoyed a breakthrough victory at the Scottish Open earlier this year, shot a 66 to sit third alongside two-time major winner Zach Johnson.
World number one and American star Dustin Johnson led a host of players tied at three under heading into the second round.
Johnson reached five under at one point, but two late bogeys derailed his momentum as he closed out the round in a share of fifth with Jason Day, world number three Justin Rose, Ian Poulter and Kevin Kisner among others.
Hideki Matsuyama, Kyle Stanley and reigning Open Championship winner Francesco Molinari were a shot further back.
Defending champion Justin Thomas, Brooks Koepka and Tommy Fleetwood headlined a group at one under.
World number two Thomas won last week's WGC-Bridgestone Invitational and he looked in good form, aside from a late wobble which resulted in two bogeys on the back nine.
Four-time champion Tiger Woods shot an even-par 70 after recovering from a shaky start.
Woods started his day with a bogey and a double-bogey, but regrouped to remain in the mix – playing his last 10 holes bogey free at three under.
Four-time major winner Rory McIlroy, who played alongside Woods, also shot a 70.
Seeking a career Grand Slam of majors, Jordan Spieth posted a one-over-par 71 to open his bid.
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