Danny Lee was pleased to make the most of his opportunities after shooting a six-under 64 in the opening round at the US PGA Championship.

The New Zealander climbed into outright second after posting eight birdies and two bogeys at Bethpage Black in New York on Thursday.

Lee, whose best major finish was a tie for 17th at the 2016 Masters, capitalised on the par-threes, birdieing three of the four shorter holes.

The 28-year-old said he was able to take his chances to sit a shot behind defending champion Brooks Koepka.

"I can't remember every single shot I hit, but the only thing I can remember is whenever I hit it on the fairway, I was able to convert that to the birdie," Lee told a news conference.

"I think I made a lot of good up-and-downs, I think, even when I missed the fairway."

On his success at the par-threes, Lee said: "My iron game has been always good, and I always have a lot of confidence in them.

"And I guess I really liked the pin locations, what they gave us, and I was able to go straight at it every single time."

While Lee was impressive, the day belonged to Koepka as the American set a new course record with his seven-under 63.

But the three-time major champion's round came as no shock to Lee.

"I wasn't surprised when Brooks shot seven under this morning. I mean, have you seen him playing U.S. Opens and PGA Championships the last three years?" he said.

"When you're hitting driver, pitching wedge every hole. I wasn't surprised at all. But it didn't change my game plan at all.

"I'm not like Brooks Koepka long, but I can carry it about 290, 300 now. My mindset was honestly some kind of under-par round would be good, but obviously I did a lot better than that and I was very pleased with it."