Tom Kim 4 off lead after opening round at PGA Championship

Tom Kim of Korea tees off on the 12th hole during the first round of the PGA Championship at Valhalla Golf Club in Louisville, Kentucky, May 16. AFP-Yonhap

Korean youngster Tom Kim is four shots off the lead after the opening round of the PGA Championship in Kentucky.

Kim is in a seven-way tie for fifth place after collecting six birdies against one bogey for a five-under 66 to open the second major tournament of the season at Valhalla Golf Club in Louisville on Thursday (local time).

Kim made the turn at two-under, and then birdied three of the first four holes on the back nine to reach five-under.

He had a hiccup with a bogey at the par-three 14th, where he found a bunker off the tee. But Kim bounced back with a birdie at the 17th, set up by an approach that landed just about five feet from the cup.

The 21-year-old, whose Korean given name is Joo-hyung, has not yet recorded a top-10 finish in 13 tournaments so far this year.

This is Kim's 10th major championship appearance. Last year, the three-time PGA Tour winner tied for second at the Open Championship and tied for eighth at the U.S. Open.

Xander Schauffele of the United States grabbed the first-round lead after tying the men's major championship scoring record with a 62.

Three American players, Tony Finau, Sahith Theegala and Mark Hubbard, are tied for second after shooting 65s. Rory McIlroy, who won the last PGA Championship held at Valhalla in 2014, is in Kim's group at five-under.

Kim gave himself a pat on the back for a "really, really solid" round.

"I played really solid on the front nine, and I was just going into the back nine with the same game plan and gave myself some good opportunities. Made some good putts coming in," he said. "Softer greens definitely helped. More experience. More scar tissues definitely gets you a tougher player, and I've been playing really good golf. Just haven't really seemed to get things going, but to do this in a major championship shows me a lot more about myself and gives me more confidence."

Schauffele teed off at 8:03 a.m. and posted his record-tying score. Kim, started his day at 1:50 p.m., said he knew Valhalla was there for the taking after seeing the low score.

"Obviously, Xander played really, really well to shoot nine-under par. But when you see a score like that, you go, OK, I guess it's playing pretty gettable and there's going to be a lot of opportunities out there," Kim said. "I think the guys who did shoot under par in the afternoon did a really good job of going after it."

Kim Si-woo of Korea watches his approach shot on the ninth hole during the first round of the PGA Championship at Valhalla Golf Club in Louisville, Kentucky, May 16. AFP-Yonhap

Kim was the only Korean inside the top 10 after the first round. Kim Seong-hyeon had four birdies and two bogeys for a 69, which put him in a tie for 32nd. An Byeong-hun, the top Korean in the world rankings at No. 23, shot an even-par 71 with two birdies and two bogeys.

Kim Si-woo and Im Sung-jae both shot 73s, while the 2009 champion Yang Yong-eun and Lee Kyoung-hoon both shot 74s. (Yonhap)