DUBLIN, Ohio — Rory McIlroy gets to play only three regular PGA Tour events this year. He showed Thursday why the Memorial Tournament was one of them.
On a Muirfield Village course that already ranks among his favorites, McIlroy had a birdie putt on his last eight holes and converted half of them on his way to 6-under 66 to join Chris Riley in the lead after the first round.
McIlroy hit the ball so pure that he shot 32 on the front nine despite missing three birdie putts inside 8 feet.
"A great way to start the tournament," McIlroy said.
The 22-year-old from Northern Ireland narrowly made the cut at Wentworth in the BMW PGA Championship and wound up in a tie for 24th. Asked the difference between last week and this week, he replied, "It's about 30 degrees warmer."
A tournament known for its sloppy weather has been spectacular, and it showed in the scoring on a well-manicured course.
Chris DiMarco and Josh Teater were at 67, followed by a large group at 68 that included Steve Stricker, Dustin Johnson, Stewart Cink and Rickie Fowler, runnerup at the Memorial last year.
Fifty-one players in the 120-man field broke par.
Luke Donald, in his debut as the No. 1 player in the world ranking, recovered from a slow start by making four straight birdies toward the end of his round for 70. He played with Masters champion Charl Schwartzel and four-time major champion Phil Mickelson, who each had 72. Mickelson did that without making birdie on the par 5s.
Riley relied heavily on his putter to take advantage of the smooth greens.
"The less I think, the better I play," Riley said. "And today, I didn't have time to think. The pace of play was so good and I didn't stand around and think about shots. I just played golf."
By giving up his PGA Tour membership, McIlroy is allowed to play only 10 tournaments. That includes the four majors and three World Golf Championships,
"This is one of my favorite weeks of the year, one of my favorite courses," he said.