KOHLER, Wisconsin: David Lingmerth rebounded from a bad stretch of golf to head to the locker room with the lead at the PGA Championship.

He shot 2-under 70 to finish the second round at 7-under 137 on a sweltering day at Whistling Straits Friday. That puts him one shot ahead of Jordan Spieth, who just completed a round of 5-under 67, Russell Henley, who is out on the course, and Dustin Johnson, who tees off in the afternoon.

Lingmerth got to 8 under after six holes but played the next three holes at 4 over par. His back nine was better, and when he dropped a 35-footer in on No. 18, he had his eighth birdie of the round and was back in the lead.

Meantime, Hiroshi Iwata is in some very exclusive company.

The 34-year-old veteran of the Japan Golf Tour just shot 63 at the PGA Championship, matching the lowest single-round score in a major.

He shot 29 on the back nine, starting with an eagle on No. 11, then five birdies over the final seven holes. He is now at 4-under 140 for the tournament, two shots off the lead.

Iwata’s was the 27th round of 63 in major history. The last came from Jason Dufner at the PGA at Oak Hill in 2013.

Johnny Miller was the first to go that low. He shot 63 at the US Open in 1973, and remains the only player to shoot that number in the final round to win a major.

Also, George Coetzee’s season seemed to stall after two early European Tour wins, but the South African wasn’t surprised by his storming second round at the PGA Championship.

“I’ve actually felt like I’ve played pretty well,” said Coetzee, who finished tied for 74th at the BMW PGA Championship at Wentworth in May and missed four cuts in five starts since then.

“It has just been kind of mentally draining. I think I played too many events and probably not focused enough on preparing for only the big ones.

“But I’m a little bit more rested this week and hopefully I’ll have the energy come Sunday.”

He assured himself of a first Sunday appearance in a PGA Championship after three prior missed cuts with a seven-under par 65 for a five-under total of 139.

The 29-year-old from Pretoria got off to an indifferent start with a 74 on Thursday at Whistling Straits.

“It’s funny how the game works,” he said. “I’ve had the same kind of swing thoughts, same game plan. Today the putts just went in. If you know you’re going to make the putts, then you can play a bit more conservative when you have to and you don’t take the silly chances.”

Coetzee posted seven birdies and an eagle in a round marred only by bogeys at nine and 18.

“I think I think after birdieing the first couple of holes, I felt like I’m playing well,” he said. “But yesterday, I birdied the first three holes and shot 74, so it’s not really something you can count on.

“But when I chipped in for par on the fourth hole, I definitely felt like, OK, maybe things are different from yesterday.”

Coetzee, who won his first European Tour title at the Joburg Open last year, plays many of his practice rounds with fellow South Africans Louis Oosthuizen, Charl Schwartzel and Branden Grace.

Both Schwartzel and Oosthuizen are former major champions, and Oosthuizen finished tied for second in both the US and British Opens this year.

Coetzee said the success of his countrymen inspires him — especially after he can pocket their money in some friendly wagering.

“We take each other’s cash on a day-to-day basis,” he said. “It’s nice to see them do well and it makes me feel like I also deserve to be among them and play against the same guys.”