Former champion Justin Thomas overcame testing conditions to set the clubhouse target on day two of the 104th US PGA Championship.
Thomas, who lifted the Wanamaker Trophy at Quail Hollow in 2017, carded a second-consecutive 67 at Southern Hills for a halfway total of 134, six under par.
That took the world number one a shot ahead of overnight leader Rory McIlroy, who was among the later starters on Friday as he continued his bid to win a fifth major title and first since 2014.
The forecast of winds gusting up to 40mph had prompted tournament officials to opt not to cut the greens before play got under way on Friday in a bid to prevent balls moving on the undulating surfaces.
Thomas immediately found the speed of the greens to his liking as he birdied the 10th, his opening hole, and also picked up another shot on the 13th to join McIlroy at the top of the leaderboard for the first time.
That was short-lived as Thomas promptly bogeyed the 14th, but that would prove to be the only blemish on the former world number one’s scorecard as he followed a run of eight pars with a birdie on the fifth and then completed a superb day’s work with a birdie on the ninth.
“(I’m) very pleased,” Thomas said. “Although I played solid yesterday, I played really, really well today.
“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. I felt we did a great job of that and am glad to have a good round to show for it.
“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.
“I just need to try to maintain that the best that I can and keep trying to play good golf.”
None of the morning starters were able to get closer to Thomas than England’s Matt Fitzpatrick, who carded two birdies and one bogey in a patient 69 to lie three shots off the pace, despite admitting he was not initially a fan of the venue.
“My dad called me and he was asking how is the course looking and, no offence to the PGA here, but I was like, it’s a typical PGA, it’s long and tough and just not really my cup of tea,” Fitzpatrick said.
“(But) this year I’ve got a lot longer and it showed a lot the first two days with the clubs that I’ve been hitting into holes. Hopefully it’s a sign of things are changing a little bit for me and will open a few more doors on other golf courses.”
World number one and Masters champion Scottie Scheffler looked set to miss the halfway cut after making a double bogey on his final hole to return a 75 and finish six over par.
Tiger Woods was battling to avoid the same fate as he approached the end of his second round, the 15-time major winner following his second birdie of the day on the 10th with a costly double bogey on the next.
Woods pulled his tee shot left and then pitched over the green into a bunker, the resulting five dropping him to five over par, one shot outside the projected cut.
McIlroy took until the 12th hole to record his first birdie of the day, the four-time major winner having dropped shots on the second and seventh in a front nine of 37.