LOUISVILLE, Kentucky (AP) ― Rory McIlroy showed no sign of letting up. Lee Westwood might just be getting started. Momentum was a big theme Thursday in the opening round of the PGA Championship, and it even applied to Tiger Woods.

Except that Woods kept going the wrong direction.

Westwood followed up a season-best 63 four days ago at Firestone by matching his best score in a major championship. He made nine birdies at Valhalla for a 6-under 65, giving him a share of the lead with Ryan Palmer and Kevin Chappell.

One shot behind was McIlroy, the No. 1 player and overwhelming favorite in the final major of the year. McIlroy, coming off back-to-back wins at the British Open and a World Golf Championship, overcame a wild double bogey on the par-5 10th hole by running off four straight birdies. His eagle attempt on the 18th hole narrowly missed. He settled for a 66, a solid start in his bid to become only the seventh player to win the last two majors of the year.

Woods achieved that feat twice, including at Valhalla in 2000. That now seems even longer than 14 years ago.

On a day when nearly half the field shot par or better, Woods opened with a 3-over 74. He hit two tee shots that missed the fairway by some 30 yards, hooked a 3-wood into a creek and hit a spectator with his tee shot on a par 3. His two best putts were for par and bogey.

“It wasn’t very good,” Woods said.

He didn’t look very sharp. In his last competitive round, Woods withdrew after eight holes at Firestone because of another back injury. He said his trainer was able to pop a joint back into place above the sacrum, eliminating the pain. But it apparently did little for the rust.

Woods wasn’t the only player who hit a few wild ones.

Right when McIlroy was building momentum, he hooked his second shot on the par-5 10th hole over a fence and out-of-bounds, leading to a double bogey.

He was more upset about a three-putt bogey on the next hole, but then Boy Wonder bounced back with four straight birdies to get right back into the mix.

“Whenever you are confident and you have some momentum on your side, it’s easier to do what I did today rather if everything is sort of going against you, and you’re struggling for form and you have a patch like that,’‘ he said. 

Everything is very much going his way right now.

It was his 11th straight round under par, and his third straight round of 66.

Westwood also had a double bogey on his 10th hole that kept his score from being even better. He played the back nine first, and hit his tee shot right down the middle at No. 1, and right at the edge of a divot that wasn’t entirely filled with sand.

”It was like caught or plugged,“ Westwood said. ”So it would have been a perfect 9-iron from the fairway, and just unlucky. Caught it a bit heavy.”

He flubbed a chip trying to be too perfect and missed a 4-foot bogey putt. Much like McIlroy, he responded in splendid fashion by closing out his round with four straight birdies, finishing with a 30-footer on the ninth hole.

Westwood also had a 65 in the third round at Congressional in the 2011 U.S. Open.

“I’ve played better rounds of golf, but I was really pleased today,” he said. “I hit a lot of quality iron shots, and it felt like 65 was a fair enough score for the way I played. I got a couple of bad breaks out there, but I rolled a couple of putts in that you probably wouldn’t expect to hole. But that‘s just the way it is. A bit of momentum is a wonderful thing.”

The timing was great for Westwood, who is trying to avoid missing the Ryder Cup for the first time since 1995. European captain Paul McGinley told Westwood he wanted to see some form, and Westwood has delivered a 63 at Firestone and a 65 in the opening round of the final major.

Chappell played bogey-free in his 65, while a late bogey was about the only thing that spoiled Palmer’s day. He was the only one to reach 7-under par, with a birdie on the seventh hole, and he allowed himself to think about two more birdies for a 62 and the lowest score ever in a major. He missed a short par putt on No. 8 and that was that.

“I wanted to get to 8 (under) so bad and it kept driving me,” Palmer said. “So we‘ll take 6 going into tomorrow.”

The course was generally soft and gentle, and it showed in the scores.

While it’s daunting to see McIlroy anywhere near the lead the way he’s playing, Valhalla offered good scores to plenty of players.

Henrik Stenson and Jim Furyk were among five players at 66. Kentucky native J.B. Holmes had a 68 despite taking a double bogey on the 13th hole when his drive landed in a divot and his next shot to the island green didn’t find the island.

Phil Mickelson played alongside Woods and rallied for a 69.

For Woods, it was the second straight round in a major when he didn’t beat the Ryder Cup captain, 64-year-old Tom Watson, who had a 1-over 72.

Watson was more interested in how his team was shaping up than his own game. Qualifying ends after the PGA Championship, and Watson gets three picks on Sept. 2.

“I’m going to with horses that are running well,” he said.

After one day, Tiger was stumbling badly. Woods’ first order of business Friday was simply to make the cut.