Thomas maintains two-shot lead at RBC Heritage

"The golf course felt completely different," said Thomas, who is chasing his first victory since he claimed the second of his two PGA Championship titles in 2022.

"It's definitely firming up," added the American. "We even noticed it just kind of on some chips, the pitch shots, some wedges -- shots that I hit very nicely, it's not spinning as much. They're getting crusty, and it's fun."

Thomas was even for the day after two birdies and two bogeys in the first 10 holes, but he rolled in a 15-foot birdie putt at the 13th then birdied the par-five 15th to give himself a two-stroke cushion over South Korean Kim Si-Woo and American Russell Henley through 36 holes of the $20 million signature event at Harbour Town Golf Links.

Kim produced the round of the day, firing an eagle and six birdies with just one bogey in a seven-under par 64.

"It was a good round," said Kim, who added that he wasn't feeling great but managed to figure some things ut on the course.

His best shot, he said, was his second at the par-five fifth, which "somehow" landed six feet from the pin to set him up for eagle.

"I think that's the start of momentum today," said Kim, who is feeling extra motivated after failing to book spot in last week's Masters.

"I got so frustrated last week watching the Masters," he said. "But somehow I've got to move on."

Henley joined him on 10-under 132 with a three-under par 68 that included four birdies.

American Andrew Novak posted a six-under 65 to share fourth on 133 with England's Tommy Fleetwood, who signed for a 66.

World number one and defending champion Scottie Scheffler was a further shot back after a one-under 70, tied with Canadian Mackenzie Hughes.

Thomas, 31, has his first 36-hole lead since 2022, keeping his nose in front despite battling an errant driver that could have proved more costly.

Thomas hit just seven of 14 fairways and 11 of 18 greens in regulation but his short game was spot on.

He came up with solid par saves on 12 and 14 and goes into the weekend with a chance to end a title drought that has included several near misses.

"I'd say the majority of (coming close) has just been pressing and trying too hard," Thomas said. "All of us, I would assume, want to win so bad, and I want to win so bad.

"That's something I feel like I did so, so well there for a couple of years is I just let tournaments come to me and I just trusted in my ability," Thomas said. "That's just really been my key this week is I'm just trying to really trust my game and commit to what I'm doing.

"I have a lot of faith and confidence in what I can do. So, I just need to let it happen."