Rory McIlroy finishes at 9-under

— -- LOUISVILLE, Ky. -- On a soggy day at Valhalla, Rory McIlroy put himself in a familiar position: leading the PGA Championship.

The overwhelming favorite from Northern Ireland started on the back side after a 50-minute rain delay Friday, made a couple of early birdies, then claimed the outright lead for the first time when he rolled in a 30-foot eagle putt at the 18th hole.

"I got lucky that the ball plugged and stayed there [on the fringe]," McIlroy said of his approach shot to No. 18. "It was nice to see that [putt] go in the hole."

McIlroy led by a stroke when he squandered a chance for his second eagle at No. 7, after sticking his second shot from 243 yards just 8 feet shy of the flag. McIlroy grimaced as the putt stayed to the right of the cup. He tapped in for a birdie that left him at 8 under, two strokes ahead of Ryan Palmer, who was in the clubhouse at 135 after shooting a 1-under 70.

Palmer opened with a 65 and shared the 18-hole lead with Lee Westwood and Kevin Chappell.

Westwood and Chappell had afternoon tee times.

McIlroy is going for his third straight win and fourth major title. He won the PGA Championship at Kiawah in 2012.

"I'm feeling good about my game," McIlroy said. "I'm confident and hit the ball well for the most part, though not as quite as well as yesterday. I feel in control of my game and my emotions and need to do that over the weekend as well."

Steve Stricker -- a 47-year-old, part-time player who was picked as an assistant U.S. Ryder Cup captain this week -- showed he's still got plenty of game. He made four birdies on his first nine holes, giving him a share of the lead until McIlroy claimed it for himself on what was shaping up to be a long day.

A steady rain forced officials to suspend the round after just 20 minutes because of too much water on the putting surfaces and fairways. Work crews already were using squeegees on the greens when another burst of showers hit Valhalla.

Play was halted as Palmer was playing the first hole. There was more rain in the forecast, raising the possibility the second round would not be completed Friday. Tiger Woods, in 109th place and in danger of missing the cut at the PGA for the second time in four years, was scheduled to play in the afternoon.

Adding to the difficulty of a soggy course, players had to contend with mud.

Championship director Kerry Haigh said the ball was to be played as it lies -- the players will not be allowed to lift, clean and place their golf balls through the green as often happens in regular tour events.

He said no consideration was given to restarting the second round using preferred lies. Once a round begins under one set of conditions, it cannot change. Haigh didn't see the need.

"We are playing the ball down," Haigh said. "Once we start the round, we will not change. Really, there was no consideration to that. The fairways are good. And the Rules of Golf allow for relief if the ball is in casual water."

While rain softened the greens, it also made the course longer.

Palmer came up short of the green from out of the rough on the 504-yard second hole, though he pitched to 2 feet to save par.

McIlroy typically enjoys soft conditions. That was the case at Firestone last week, and he said he was "licking his lips" when he saw the course. McIlroy rallied from a three-shot deficit to win the World Golf Championship, his second straight victory after a wire-to-wire triumph at Royal Liverpool in the British Open.

McIlroy won his first major at rain-softened Congressional in the 2011 U.S. Open with a record score of 16-under 268.

The Associated Press contributed to this report.