Hideki Matsuyama took a share of the lead after firing a seven-under 65 on day one of the Memorial Tournament in Ohio.
The Japanese finished atop of the leaderboard alongside Abraham Ancer and Joaquin Niemann after a round that included a brilliant birdie-birdie-birdie-birdie-eagle run between the 13th and 17th holes.
The 337-yard drive on the penultimate par-four hole capped off a round that also included three birdies on the front nine, with two bogeys on the 10th and 11th the only blemishes of his day.
Ancer, of Mexico, and Chilean Niemann matched Matsuyama on 65, both shooting eight birdies apiece and one bogey each to sit in joint first out of a world-class field which features eight of the world's top 10.
Rory McIlroy, who won for the first time since September 2016 at the Bay Hill Invitational in March and finished second in the BMW PGA Championship on Sunday, was even at the turn after a birdie on the sixth hole and a bogey on eight.
The Co Down man got a shot back with a birdie on the 13th, but double bogeyed the 14th to finish tied in 74th on two-over 74.
Shane Lowry was one shot better, his round containing four birdies, three bogeys and a double-bogey.
Tiger Woods, who shot the highest score of his career at Muirfield Village with an 85 in the third round on his last appearance in 2015, finished in joint 47th on 72.
The five-time Memorial winner started his round from the 10th and was four over par after seven, but fought back to shoot level par.
Playing partner Justin Rose, who won last week in Fort Worth and will become world number one with another win here, bogeyed the last to shoot one under.
In his first tournament as world number one, Justin Thomas joined Woods on 72 after hitting his second shot out of bounds on the par-five seventh for a double bogey.