LOUISVILLE, Ky. – First-round co-leader Ryan Palmer had just slogged his way through a gritty round of 1-under-par 70 and sat at 7 under through 36 holes of the PGA Championship. He had danced through Friday's off-and-on raindrops to close with back-to-back birdies for the second straight day at Valhalla Golf Club.

And then, sitting in front of a backdrop listing the previous 95 PGA champions, Palmer shifted the focus from his round to reality.

"Rory is the guy to beat, to be honest," Palmer said.

There's a sobering truth to golf these days: It's Rory McIlroy's reign, and everybody else is just splashing around in it.

Yes, 36 holes still need to be played at Valhalla, but McIlroy's seemingly casual jaunt to a 4-under 67 in conditions only a Northern Irishman could love has the world's top-ranked player bearing down on a third straight victory and second straight major.

At 9-under 133, he takes a one-stroke lead over Jason Day and Jim Furyk into Saturday's third round. Palmer and Rickie Fowler sit two back, while Phil Mickelson jazzed the crowd with an eagle on the par-5 18th to move to 6 under.

"I'm clearly not the favorite," Day said. "Rory's hitting the ball longer and straighter than pretty much everyone in the field."

McIlroy's run, which includes a dominant performance in the British Open, has even him at a loss — a rarity these days.

"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."

He said he's winning at a little psychological game he plays in his head.

"I'm staying in the present and have little trigger words I'm using that seem to be getting me through," McIlroy said. "I can't really explain it any better than that.

Perhaps numbers can. McIlroy is now 41 under par in his past 10 competitive rounds, six of them played in the pressure cooker of major championships.

Is now the time to mention McIlroy missed a short eagle putt on the par-5 seventh — which would've been his second eagle of the day — and left a birdie putt on the par-3 eighth on the lip?

"When he hits the driver that straight and that long, and the short game is incredible, it's very difficult to beat him," U.S. Open champion Martin Kaymer said. "His iron shots, they are very solid. He doesn't miss many golf shots. So you just have to respect it a lot, how good he plays. There's nothing wrong with his game."

McIlroy took bogey on the tough par-4 second hole, and then had to scramble for four straight pars. But on the par-5 seventh, after another big tee shot on the left side of the fairway, he hit a 5-wood over the water to 8 feet, a shot that reminded everyone that he's the class of golf. That was one of the few putts he missed — he still made birdie — and McIlroy finished with a 15-foot birdie on the final hole.

Fowler saw it during the final round at Royal Liverpool last month. He knows what kind of work is left for the guys chasing.

It can be done. But they might need some help from McIlroy.

"He's the best player in the world right now," Fowler said. "And I would say a lot of that is his confidence right now with the way he's driving the ball. If he continues to drive it, he's going to continue to be in contention at a lot of golf tournaments and win a lot of times."

Day shot the day's low round, a 65 that included an eagle, as the weather calmed for the afternoon rounds. That was also when Fowler — who owns top-five finishes in all three previous majors this year — Mickelson and Furyk played.

Torrential downpours dumped an inch of rain and forced a 50-minute delay just 20 minutes after four groups had started.

"I wasn't sure if we should have teed off, to be honest," Palmer said. "You could barely see the fairway."

Palmer's group could see the first green upon arrival. Well, they could see it was mostly underwater.

"We were questioning why we had to hit a second shot into a green that's already half in standing water," Palmer said. "They said, 'That's just golf.' We're like, 'Tell the guy indoors that's making the decision to come check it out because it's wet.' "

The conditions weren't stopping McIlroy, who said his experience blowing the 2011 Masters as a 21-year-old helped teach him how to be a front-runner. That was when he turned a four-stroke 54-hole lead into a tie for 15th with a final-round 80.

"I went into protection mode once in my career," McIlroy said. "That didn't work out very well. So I said to myself, 'I'll never do that again.' "