LOUISVILLE, KENTUCKY – Lee Westwood stormed into a share of the PGA Championship lead with five birdies in his last six holes on Thursday as four-times winner Tiger Woods ended the opening round a distant nine shots off the pace.

Westwood, long regarded as one of the best players in the game who has yet to clinch a major title, fired a six-under-par 65 on a calm, muggy day at Valhalla Golf Club to finish tied for the lead with Americans Kevin Chappell and Ryan Palmer.

British Open champion Rory McIlroy, the pre-tournament favorite, was lurking ominously just one off the pace after opening with an eight-birdie 66 in the year’s final major.

“I played well, hit a lot fairways, putted nicely,” former world No. 1 Westwood told reporters after racking up a total of nine birdies, one bogey and a double on a challenging 7,458-yard layout offset by soft and receptive greens.

“I gave myself a lot of chances. All in all, there were no real weaknesses out there. I hit a lot of quality iron shots, and it felt like 65 was a fair enough score for the way I played.”

Westwood rebounded from a double-bogey at the par-four first, his 10th hole of the day, with birdies on the fourth, sixth, seventh, eighth and ninth to end his round with a spectacular flourish.

Chappell, who missed the cut in his PGA Championship debut last year, recorded three birdies on each nine while Palmer briefly got to seven under for the outright lead before he bogeyed his penultimate hole, the par-three eighth.

McIlroy, with his game in sparkling order, birdied three of his first nine holes to reach the turn in three-under 32 before he hit his second shot on the 10th out-of-bounds en route to a double-bogey. He then bogeyed the par-three 11th.

However, the Northern Irish world No. 1 responded in spectacular fashion, reeling off four consecutive birdies from the 12th, before picking up another shot on the par-five last where he comfortably reached the green in two and two-putted.

“You have to take whatever you are feeling inside and try and turn it into a positive,” McIlroy said of his rocky ride over 10 and 11. “I was ‘hot’ and it’s (all about) trying to use that fire as a fuel to propel yourself forward.

“I think it just shows where my game is mentally right now, that I was able to do that today,” added McIlroy, who ended the day tied with American Jim Furyk, Italy’s Edoardo Molinari, Swede Henrik Stenson and Englishman Chris Wood.

Woods, who pronounced himself pain-free on Wednesday after suffering a back scare on Sunday that left his participation in some doubt, struggled on the way to a three-over 74 as the field had to contend with some tough pin positions.

Watched by huge galleries after teeing off from the 10th in a high-profile grouping with former champions Phil Mickelson and Padraig Harrington, Woods looked rusty as he mixed four bogeys with a lone birdie and totaled 30 putts.

“It wasn’t very good,” said Woods, who clinched the most recent of his PGA Championship titles in 2007 and has been stuck on 14 major wins since his triumph at the 2008 U.S. Open.

“A lot of bad shots and I never got a putt to the hole. For some reason, I thought they were going to be a little bit quicker and I didn’t make the adjustment well enough.

“My swing was dialed in on that (practice) range out there. Unfortunately, I didn’t carry it to the golf course.”

Woods dropped his first shot of the day at the par-three 11th where he missed the green to the right, then chipped 13 feet past the cup before failing to make the par putt.

His tee shot at the par-three 14th sailed way left and again he failed to get up and down for par, but he picked up an unlikely birdie on the par-four 16th when he holed out from 34 yards in the middle of the fairway.

Hideki Matsuyama shot an even-par 71, canceling four birdies with four bogeys.

Matsuyama, who teed off with an early group on the back nine, sank a curling 25-foot putt to grab a birdie on No. 12, and added another with a wedge approach on No. 13 that stopped within two feet of the hole.

“Some (parts of my game) were good, but toward the end I wasted my good shots by following them with errors,” Matsuyama said.

“It was a shame (to finish poorly), because I had gotten to three under at one point. But to get around the course in even par is not bad, all things considered.”