(Photo credit: Bill Streicher-Imagn Images)

NEWTOWN SQUARE, Pa. -- Even after World No. 1 Scottie Scheffler joined a seven-way tie for the lead, the main character from the first round of the PGA Championship was Aronimink Golf Club, which stymied some of the best in the world and set the tone for a challenging week.

Scheffler shot a 3-under-par 67 Thursday, after Aldrich Potgieter of South Africa, Min Woo Lee of Australia, Ryo Hisatsune of Japan and German Stephan Jaeger posted the clubhouse lead in the morning wave. Alex Smalley and German 41-year-old Martin Kaymer -- 16 years removed from his PGA Championship victory -- matched them in the afternoon.

A heavily bunched leaderboard saw another seven players at 2-under 68 and at least 19 more at 1-under 69. Patrick Reed's 68 was the only bogey-free round of the day; he is tied with Xander Schauffele, Max Greyserman, Sahith Theegala, Ireland's Shane Lowry, Canadian Corey Conners and Englishman Daniel Brown.

Major winners Brooks Koepka, Jordan Spieth, Justin Thomas, Collin Morikawa, Jon Rahm of Spain and Australians Jason Day and Cameron Smith are lurking at 1-under 69. Rahm holed out for eagle at No. 2 and chipped in for birdie at the par-3 eighth before a closing birdie at No. 9.

But after his round, Rahm was one of many to comment on Aronimink's surprising difficulty.

'There was somebody earlier in the week where -- there was some chatter where people thought 15- to 20-under was going to win. And I think that got to somebody in the PGA, and they did something about it,' Rahm said with a slight smile. 'Because if the golf course stays like this and it keeps firming up, yeah, obviously it's not going to be anything like that.'

Fifteen of the past 17 PGA Championships had a winning score of 8 under or better. The two exceptions were recent: Phil Mickelson went 6 under in 2021 and Thomas was 5 under in 2022. But as recently as 2024, the PGA champion (Schauffele) soared to 21 under par.

It is the second time Aronimink has hosted the PGA Championship after Gary Player won in the Philadelphia suburbs in 1962.

Players noted the front/back split, with most players faring well on the front nine but losing ground on Nos. 10-18. Four of the five toughest holes relative to par came on the back nine, while the par-3, 245-yard eighth played closer to a par-4 with a scoring average just above 3.5.

Jaeger birdied four of his first six holes to race in front; all four of those birdie putts came from at least 13 feet away, including 39 1/2 feet on No. 4 and 22 feet on No. 5.

A 36-year-old grinder without a top-20 finish at a major, Jaeger cooled off on the back nine having capitalized on soft greens early in the morning after some overnight rain.

'The front is a little more scorable than the back, shorter, a lot of wedges in,' Jaeger said. 'So I felt like I took advantage of that. Yeah, kind of kept it together on the back.'

Hisatsune, 23, poured in four of his seven birdies on the back nine to join the other leaders, but he was hurt by four bogeys. Potgieter, 21, scored similarly well with six birdies on his card.

Spieth briefly held a share of the lead on his second nine before he chased birdies at Nos. 5-6 with bogeys at Nos. 7-8.

Garrick Higgo of South Africa was less than 60 seconds late to his tee time and incurred a two-stroke penalty on the first hole. But he rebounded to score a 1-under 69 -- meaning he'd be tied for the lead without the penalty.

Higgo attempted to plead his case in the scoring tent.

'I was just trying to get evidence. I feel like any of you would have done the same,' Higgo declared. 'It's kind of -- I was there on time, but the rule is, if you're one second late, you're late. So if you think about it, I was there on time, if you know what I mean.'

Rory McIlroy of Northern Ireland, playing alongside Rahm and Spieth in the morning, hit just five of 14 fairways in regulation and turned in a 4-over 74. Bryson DeChambeau faltered on his approaches and with the flatstick, posting a 6-over 76 with no birdies until his final hole.

Other notables included Rickie Fowler, J.J. Spaun, England's Matt Fitzpatrick and Japan's Hideki Matsuyama at even-par 70; Cameron Young at 1 over; and Sweden's Ludvig Aberg, Australian Adam Scott and Englishman Tommy Fleetwood at 2 over.

Fan favorite Michael Block opened with a 70, the top score of the 20 PGA teaching professionals in the field and a lower round than several elite players in the field. Block was the breakout star of the 2023 PGA Championship, making the cut and tying for 15th with a hole-in-one during the final round.

--Adam Zielonka, Field Level Media