DUBLIN, Ohio — Dustin Johnson set the pace early with 10 birdies on his way to 8-under 64 at the Memorial.
Jason Day avoided his aggressive nature to try to catch him Thursday.
One day after Jordan Spieth referred to Johnson as the most talented player on the PGA Tour, Johnson opened with three straight birdies, made three straight birdies to close the front nine, added four in a row on the back and finished with his best score in his nine years at Muirfield Village. He had a one-shot lead over Brendan Steele, who holed out for eagle on the 18th for 65.
Day, the world's No. 1 player and a Muirfield member, played in the afternoon as clouds began to gather. He rallied on the back nine with three birdies and an eagle, and wound up two shots back, which was fine with him. His 66 was his best score in competition on the course Jack Nicklaus built.
"Mr. Nicklaus told me early, 'Just play within yourself.' Being patient is key out here," Day said. "When you see 8 under, it's hard to be patient. But pleased."
Spieth's putter saved him in a scrappy round of 70.
Rory McIlroy, playing with Spieth, changed back to a conventional putting grip. That helped only so much in his round of 71.
Much attention was on the top three players in the world — Day, Spieth and McIlroy — because of their ranking, having won five of the past seven majors, and because all three arrived at the Memorial coming off victories.
Johnson, with his power and, Thursday, his putting, showed why Nicklaus and others think the Big Three will grow in size.
"I just played well right out of the gates," Johnson said. "This year I've felt like I'm playing well. I just haven't quite played up to my potential. With me, it has everything to do with the putter. I rolled it well today."
Matt Kuchar holed a 15-foot par putt on the 18th hole to join the group at 66 that included Hudson Swafford, who did all his damage on the front nine when he tied the course record with 29.
Luke Donald was among those at 67, and Phil Mickelson was at 68, partly due to a wild shot on No. 15. Mickelson beaned a marshal in the head, and the ball kicked back across the fairway and led to birdie on the par-5 hole.
Valspar tourney boss sees little impact due to Doral
With the tour's announcement Wednesday that the World Golf Championship tournament at Doral Country Club near Miami will move to Mexico City for at least the next seven years, Innisbrook's Valspar Championship now will follow a tournament outside Florida.
Will that make it harder to attract top players to Palm Harbor?
Not really, tournament director Tracy West said. Because the Mexico City tournament will provide a charter jet for players to Tampa after that tournament, West said she thinks she might even be able to improve the field.
"From our perspective, I don't think it's going to change anything,'' West said. "I think the players that normally play here will still play us. I don't think the extra travel will impact us. … We're making it as easy as possible (with the charter).
"I'm going to be targeting the guys who play in the World Golf Championship who don't normally play here. I'm going to say, 'Hey, you're landing in Tampa.' It might help us. I don't think it will have an impact, and maybe we get a few guys that we wouldn't normally get.''
Times staff writer Rodney Page contributed to this report.