Lance Murphey / AP

Phil Mickelson, center, jokes with Padraig Harrington, left, and a caddie before teeing off on the 10th hole, his first hole of the first round Thursday.

He could not have scripted a better start to his round, opening with an approach to 5 feet for birdie and holing a 25-foot birdie putt on the next hole, the par-3 11th.

Asked if it felt like a typical round, he replied, “Once we got going.”

“I felt a little rusty, but I made a couple of birdies early, and that made it more relaxed,” he said.

He made a bogey from a bunker was among the leaders until his only poor shot of the day at the worst spot, from the 18th tee. His ball went left into the pond, and Mickelson took double bogey.

He excited his following with a 3-iron around a tree and over the water on the par-5 third for a two-putt birdie, but gave that back when he three-putted the next green, having to make a 4-footer for his bogey.

Olazabal played four rounds at the Memorial, failed to make it through 36-hole U.S. Open qualifying on Monday and still hurts from injuries that have limited his play in recent years. He sure wasn’t expecting a 66, or his name atop the leaderboard.

“But that’s the game of golf,” he said. “I played pretty solid today and managed to score well. I have to say that the greens were a little soft after the rain, and I think that helped a little bit.”

Jerry Kelly was among those at 67, an important start because a victory would his second this year and get him to Bethpage Black.