Brooks Koepka dismissed concerns over his knee, insisting he does not have to be "100 per cent" after impressing on day one of the US PGA Championship.
Koepka ended the opening round two strokes behind leader Corey Conners and tied for second position following his three-under-par 69 on Thursday.
American star Koepka has been plagued by injuries since winning back-to-back PGA Championships in 2019 and a fourth major title in three years, undergoing knee surgery in March before missing the cut at last month's Masters.
Koepka overcame a slow start after double-bogeying his opening hole in windy conditions as he made history in South Carolina.
The four-time major champion has opened the PGA Championship with a score in the 60s in each of the last six years, the longest such streak at any major in the modern era (since 1934), eclipsing Jack Nicklaus (five – 1972-1976 Masters).
"It's a major. I'm going to show up," Koepka said when asked about his fitness and whether it was the best he has felt since returning from injury. "I'm ready to play. I've been itching to do this since Augusta.
"I mean, I feel so much better now. I don't need to be a hundred percent to be able to play good."
"I love it when it's difficult," said Koepka. "I think that's why I do so well in the majors. I just know mentally I can grind it out. Like when it's windy like this, it's not so much putting, it's more about ball striking, and I felt like I struck it really well today. I feel like that's why I've done really well.
"You've got to understand that sometimes par is a good score. You've got to understand that 30, 35 feet is a great shot sometimes, and you've just got to accept it and move on."
Defending champion Collin Morikawa closed out day one a shot further back at two under.
Morikawa mixed five birdies with three bogeys to end the round three strokes off the pace at Kiawah Island Golf Resort.
He played alongside big-hitting Bryson DeChambeau (72) and praised the reigning U.S. Open champion.
"I think people need to give him credit, starting today, that he's actually picking up the pace," Morikawa said. "It was amazing how fast he actually played. I'm not going to say fast, but he wasn't slow. You weren't just waiting on him to figure out whatever.
"Kudos to him because it was windy and he had to figure out some stuff for sure. But I enjoy it. He's a character. He's his own person. That's what makes Bryson, Bryson. I think that's why people love him. I enjoy playing with someone like that. It's not going to faze me that he hits it a hundred past me. I know I can still hit it and play golf."
DeChambeau, who heads into the second round tied for 31st, added: "The wind just kicked my butt. It's hot. Just grinding out there, it takes a lot out of you. Working really, really hard to hit every shot the exact way I want to, and then it doesn't happen, and you've got to be comfortable with it and going, okay, how do I get up-and-down.
"It's windy and you're over a four-footer. Wind is blowing really hard, and you think it's going to break. When the wind stops, it's not going to break. It's all just a really difficult thing that you've got to control out there. It's a lot of work."