Brooks Koepka made a dream start to his title defence at the WGC-FedEx St. Jude Invitational after matching his career-low round on the PGA Tour.
Koepka carded an eight-under-par 62 for a two-stroke lead following the opening round of the World Golf Championships event in Memphis on Thursday.
The four-time major champion – who has missed two cuts in his past three outings heading to TPC Southwind – was almost flawless at the PGA and European Tour tournament.
Koepka, troubled by a knee injury that has led to just one top-10 finish in 10 tournaments this year, raced out of the blocks with four consecutive birdies before closing out the front nine with back-to-back gains after dropping the seventh.
The American star was bogey free after the turn, birdieing the 11th, 13th and 16th holes to top the leaderboard ahead of countrymen Rickie Fowler and Brendon Todd.
Kang Sung-hoon is outright fourth on five under, a shot ahead of 2018 champion Justin Thomas, Matt Kuchar, Chez Reavie and Max Homa, while the likes of Phil Mickelson and Sergio Garcia are three under through 18 holes.
Former world number one Jordan Spieth endured a mixed round, posting a double bogey, two bogeys and six birdies for a two-under-par 68 – a score matched by players such as Jason Day, Bubba Watson and Xander Schauffele.
Dustin Johnson, the 2016 winner who withdrew from last week's 3M Open, signed for a first-round 69 to be a shot better off than world number one Jon Rahm.
Rahm dethroned Rory McIlroy as the world's top-ranked golfer after winning the Memorial Tournament earlier this month and the Spanish star opened his Memphis campaign with four bogeys and four birdies.
He performed a lot better than McIlroy, who carded a three-over-par 73 to leave himself with plenty of work to do heading into Friday's second round.