Defending champion Hideki Matsuyama of Japan opened with a bogey-free 8-under-par 64 and tied Bo Van Pelt for the lead in the Memorial Tournament at Muirfield Village Golf Club in Dublin, Ohio.
The 21-year-old Matsuyama, who won six times on the Japan Golf Tour, carded four birdies on each nine, including four in a row through the 14th hole.
“I don’t know what happened overnight, but I just caught magic” said Matsuyama, who did not feel confident with his game heading into the tournament even though he has seven top-10 finishes on the PGA Tour this season.
“To be honest with you, when I made the turn at 4-under, I was just trying to hold onto 4- under. And then to make a couple more birdies, it was a real bonus.”
Van Pelt, whose only PGA Tour victory came in the 2009 U.S. Bank Championship in Milwaukee, collected 10 birdies that included five in a row through No. 9 and held the lead until making a bogey on the 17th hole when he could not get up-and-down from a greenside bunker.
Jason Dufner holed a 60-foot eagle putt on the 16th hole but gave both shots back with a double-bogey 6 on the final hole when he drove into the water and posted a 66 to tie for third with Russell Knox of Scotland, who was bogey-free until stumbling at No. 9 to end his round.
Ryan Moore holed a five-foot eagle putt on the fifth hole but had a double bogey-5 on the 16th in a round of 67 that left him in a tie for fifth with Ken Duke, Brendon Todd, Harris English, Kevin Kisner, Kyle Reifers and David Lingmerth of Scotland.
Masters champion Jordan Spieth carded a 68 and was in a the for 12th that included Justin Rose of England, Keegan Bradley, Patrick Rodgers of Stanford and Pat Perez of San Diego.
Phil Mickelson recorded a 72 to tie for 68th and five-time Memorial champion Tiger Woods played the front nine in 4-over 40 before coming home in a bogey-free 33 and tied for 85th at 73.