Rory McIlroy delivered his best opening round in a major since a 65 at the 2011 US Open which he had won for his first major title.
Rory McIlroy has fired his best opening round at a major in 11 years to seize the lead at the PGA Championship, while Tiger Woods struggled in his second comeback event after severe leg injuries.
Sparked by four consecutive birdies, matching his longest such run in a major, McIlroy delivered his best opening round in a major on Thursday, since a 65 at the 2011 US Open which he won for his first major title.
"It was a great start to the tournament," McIlroy said. "It was nice to get off to that good start and sort of keep it going."
Four-time major winner McIlroy started on the back nine with 15-time major winner Woods and Jordan Spieth before a huge crowd.
Woods, who returned last month at the Masters 14 months after a car crash left him unable to walk for months, birdied the 10th and par-3 14th but made bogeys on six of his last 10 holes to shoot 74 while Spieth, chasing a win for a career Grand Slam, stumbled to a 72.
"Off to a good start," Woods said. "Hit a lot of bad iron shots late. I just never got the ball close to have any good birdie putts. I kept putting it into bad spots. It was a frustrating day."
'Sticking to the game plan'
McIlroy, who last led a major round at the 2014 PGA, has had poor major starts but the Masters runner-up reeled off four consecutive birdies from the 12th through 15th holes.
The 33-year-old from Northern Ireland put his approach inches from the cup and birdied the par-4 12th, escaped a bunker for a tap-in birdie at the par-5 13th and made a 26-foot birdie putt at the par-3 14th.
"When your game is feeling like that, it's just a matter of going out there and really sticking to your game plan, executing as well as you possibly can," McIlroy said.
McIlroy sank a nine-foot birdie putt at 15 to take the solo lead and kept it with par saves at 16 thanks to a chip to two feet and a six-foot putt at 18.
McIlroy sank a 14-foot birdie putt at the second and an 11-foot birdie at the par-5 fifth, but missed the green and made bogeys at the par-3 sixth and par-3 eighth holes before closing at the ninth with a birdie putt from just inside 19 feet.
Former world number one Woods, now ranked 818th, said his surgically repaired right leg was "not feeling as good as I would like it to be."
Three-time major winner Spieth made three bogeys in four holes starting at 15 on his way to a 72.
The world's three top-ranked golfers played together with over-par results.