LOUISVILLE, Ky. – Rory McIlroy tracked the flight of his drive as long as he could against the rain clouds over Valhalla on Friday, not quite sure where it landed. He turned to his caddie for confirmation and asked, “Was it good?”

“Beautiful,” J.P. Fitzgerald replied, his eyes still fixed on a shot that traveled 311 yards down the middle.

Such is the state of McIlroy’s game at the PGA Championship.

The world’s top-ranked player produced superior shots with his long game. He made the right putts Friday in a round of 4-under-par 67. And even with a one-shot lead over Jason Day (65) and Jim Furyk (68) going into the weekend, there was an ominous feeling at the final major tournament of the year.

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“When I’m playing like this, it’s obviously very enjoyable,” McIlroy said. “I can’t wait to get back out on the course again tomorrow and do the same thing all over again.”

It used to be that way for Tiger Woods.

But on a day McIlroy posted his 12th straight round under par, Woods hobbled away with a sore back. Woods (74) missed the cut by five shots.

Woods said he had the “same feeling, same pain, same spasms” that caused him to stop playing Sunday in the Bridgestone Invitational in Akron, Ohio. He had lower-back surgery in March, but said this pain is in a different area.

Referring to his back, Woods said, “It was telling me on the range that it probably wasn’t a good idea (to play). I couldn’t make a backswing. I can’t get the club back.”

McIlroy, who was at 9 under for 36 holes, picked up his third major — and the third leg of the career Grand Slam — last month at Royal Liverpool in a wire-to-wire victory at the British Open. He followed with a comeback victory last weekend in the Bridgestone.

Rickie Fowler (66), who tied for second in the last two majors; Mikko Ilonen (68); and Ryan Palmer (70) were at 7 under.

Phil Mickelson (67), a five-time major champion, made an eagle on the last hole and was at 6 under.

Kevin Chappell (74), who owns a home in Kirkland, was tied for 17th at 3 under. Ryan Moore (68) of Puyallup was tied for 38th at 1 under.

Chappell, Palmer and Lee Westwood were tied for the lead after the first round. Westwood (72) is four strokes behind McIlroy.

McIlroy is dangerous when he gets in the lead, especially at a major. He learned his lesson at Augusta National in 2011 when he tried to protect a four-shot lead in the Masters and wound up shooting an 80. He bounced back for an eight-shot romp at the U.S. Open and, a year later, won the PGA Championship by a record eight shots.

“If I’m two ahead going into the weekend here, I’m going to try to get three ahead,” he said.

Other tournament

Inbee Park took the second-round lead in the Meijer LPGA Classic, birdieing her first three holes en route to her second consecutive 5-under 66 in Belmont, Mich.

Suzann Pettersen (64) was a stroke back at 9 under.

Jimin Kang (70), a graduate of King’s High School in Shoreline, was tied for 25th place at 1 under.

Those with scores of 145 or worse missed the cut, including ex-Washington Huskies players Louise Friberg (73-73—146) and Anya Alvarez (76-74—150).