American Thomas cards a second consecutive three-under-par 67.

TULSA, OKLAHOMA (REUTERS) - Howling winds greeted the early starters at the PGA Championship on Friday (May 20) but Justin Thomas remained a picture of calm as he negotiated his way around the course to grab the early second-round clubhouse lead at the PGA Championship.

American Thomas carded a second consecutive three-under-par 67 at Southern Hills Country Club to reach six-under on the week and a 134 total that matched his best opening 36-hole score in a major championship.

"The conditions were obviously very difficult. I stayed very patient, tried to get in my own little world and get in a zone and just tried to execute each shot the best I could," said world number nine Thomas.

"I felt we did a great job of that and am glad to have a good round to show for it."

Thomas began his day on the back nine as flags were flapping frantically around the course and displayed remarkable distance control in windy conditions in a round that had one bogey.

The former world number one, whose sole major triumph came at the 2017 PGA Championship, birdied his first and fourth holes before dropping a shot at the par-three 14th where his tee shot landed in a front left greenside bunker.

Thomas moved into a share of the lead with Rory McIlroy, who had yet to tee off, when he birdied the 660-yard par-five fifth despite finding a fairway bunker off the tee.

The 14-time PGA Tour winner then grabbed the outright lead at his final hole, the par-four ninth, when he rolled in a nine-foot birdie putt.

"We're halfway through so it's still a long way from home, but I'm very, very pleased with where everything is at and the frame of mind and state of mind that I'm in," said Thomas.

"Just need to try to maintain that the best that I can and keep trying to play good golf."

Overnight leader McIlroy went out late and was even par through one hole and five under on the week.