INCHEON, South Korea -- Katherine Hull shot a 6-under 66 to open a two-shot lead over Amy Yang after the first round of the LPGA's Kolon Championship on Friday.

Defending champion Suzann Petterson struggled to a 5-over 77 in windy, gloomy conditions at the new Sky 72 golf club in Incheon, just to the west of Seoul. Petterson made the turn at 4-over and managed only one birdie in her round.

Hull, ranked No. 35 in the world, didn't have nearly as much trouble. She shot 3-under on the front side and, after a slip-up at the par-4 11th, birdied four of her final six holes to take the early lead in the $1.6 million event.

"Everything kind of clicked today," Hull said. "I only made probably a couple bad swings, and I putted well all day and made a couple of good par saves, and then I was able to make a few birdies. I just stuck to my routine today finally, and it paid off."

The Australian has been playing her best over the second half of the season. She hasn't missed a cut since the Wegmans LPGA in June, finishing in the top 10 five times, and won the CN Canadian Women's Open in August.

"It's nice to actually be the one that everyone is chasing, as opposed to the one doing the chasing. I've been doing that a lot lately," Hull said. "I'm happy with the way I'm playing and I believe I can win. I've just got to go out there and execute it."

Yang got to 5-under through 11 before the local star stumbled to a pair of bogeys over the final five holes.

"If I could play like this for the next two days, I think I'll finish well," Yang said. "It's my first professional tournament in Korea, so I was pretty nervous. [But] I was happy with the results today."

Fellow South Korean Chae Young Yoon is one shot back in third, and eight others were in a pack at 2-under, including Christina Kim and Mi Hyun Kim.

Se Ri Pak was in a group at 1-under. Morgan Pressel shot an even-par 70, and Paula Creamer struggled to a 3-over 75.