Jordan Spieth's pursuit of the career Grand Slam got off to a rollercoaster start Thursday at the PGA Championship, as the three-time major winner navigated a challenging day at Aronimink Golf Club with a mix of brilliance and frustration. After turning at 1-under, Spieth caught fire on his front nine—the back nine of the course—birdieing three of the first six holes to join the early leaders at 3-under. But momentum slipped away with consecutive bogeys at Nos. 7 and 8, leaving him to settle for a 1-under 69. Still, with three rounds to play, he remains firmly in contention.

"I struck the ball well," said Spieth, now making his 10th attempt to complete the career Grand Slam with a PGA Championship victory. "I was in a good position on a lot of holes. If I drive it like that, I'd expect to shoot what I did or better. Just didn't quite finish the way I wanted to the last three holes, but under-par was a good score."

The morning chill and gusting winds made Aronimink a tough test early on, but as temperatures rose, so did Spieth's game. He rolled in a 15-foot birdie putt on the par-4 16th, then drained a 10-footer at the first after the turn. Following that up with putts from just over three feet at No. 4 and just under seven feet at No. 5, he looked poised for a low round. But the final stretch proved unforgiving.

"It's one of those rounds where I feel like I played better than I scored, which is frustrating because you want to get the most out of your round," Spieth reflected. "It's also a good thing, which means things are in a good spot."

Spieth's last major victory came at the 2017 British Open, and his only top-10 finish at the PGA Championship was at Bethpage Black in 2019. Meanwhile, Justin Thomas, a two-time PGA winner (2017, 2022), kept his hopes alive with a remarkable 53-foot bogey save at the 14th hole. Thomas was tied for the lead at 3-under before giving two strokes back down the stretch, but remains in the mix as the tournament unfolds.