Im Sung-jae conjured a hole-in-one and a closing eagle to cap a 10-under par 61 on Friday to share the early clubhouse lead over a red-hot Jordan Spieth at the PGA Tour CJ Cup Byron Nelson.
South Korea's Im played alongside three-time major champion Spieth, and they produced plenty of morning fireworks at TPC Craig Ranch, where Spieth's nine birdies included six in a row on his back nine.
"I was hurting my head trying to figure out what our best ball was," Spieth said. "I think it was 57, which is pretty good."
Im was in the clubhouse on 13-under 129, where he was joined by Japan's Kensei Hirata who carded a 65.
Spieth had a 36-hole total of 12-under 130, tied with fellow American Tyler Duncan, with overnight leader Taylor Moore on 11-under after a second-round 69.
The afternoon starters chasing them included world No 1 and defending champion Scottie Scheffler and five-time major winner Brooks Koepka – who was one shot off the lead after the opening round.
Im and Spieth teed off on 10 and Im had four birdies before his only bogey of the day at the 18th.
He birdied the first, third and fourth holes before watching in apparent surprise as his five-iron off the tee at the par-three seventh bounced on the green and rolled in the cup.
"I was surprised, but I hit a really good shot," he said, calling the moment "a little unexpected but obviously very exciting."
Im, whose 2026 campaign got off to a delayed start after a January wrist injury added a 14-foot eagle at the par-five ninth to put himself firmly in the mix heading into the weekend.
Spieth, the former world No 1 who hasn't cracked the top 10 in a PGA Tour event since last year's Memorial, said his putting was key as he "drove it horribly – like, really badly. But putting was the best."
Spieth had two birdies in his first nine holes then caught fire coming in, starting with a 12-foot birdie at the first. He drained a 20-footer at the second, another 12-foot birdie at the third, a six-footer at the fourth, a four-footer at the par-five fifth after missing the green, and a nine-footer at the sixth.
"It was really fun," Spieth said. "You're feeding off each other, right? There's a lot of good golf going on."
Hirata had six birdies without a bogey to put himself in position to challenge for a first PGA Tour title.
The 25-year-old rookie said he's relishing the "great experience" of his first season on tour, even the bad weeks.
"I learn to not give up," he said. "Just keep going."