SAN MARTIN (California) • South Korea golfer Park Sung Hyun charged to a two-shot lead after the second round of the US Women's Open on Friday, with world No. 1 Lydia Ko in hot pursuit.

Park, who has three wins on the Korean Tour and is playing her first season on the LPGA circuit, birdied seven of her first 16 holes on the way to a sparkling six-under-par 66 at the CordeValle Golf Club in San Martin, California.

Her eight-under total of 136 puts her two strokes clear of fellow Koreans Amy Yang (71) and first-round leader Lee Mi Rim, who faltered with a 74.

Park, who made her LPGA Tour debut at the Founders Cup in March, said she had benefited from a strategy of simply enjoying herself on the course.

"Coming to the tournament, I didn't even think about winning because this is the first time for me," she said of her maiden US Women's Open. "I'm trying to enjoy this tournament. That's why I am comfortable."

Ko, seeking her third major title at the age of 19, followed her opening 73 with a seven-birdie 66 to be three shots off the pace.

"I didn't start off very well, missing the fairway on one," said Ko, who began her round with a bogey and ended it with a four-foot putt for birdie at the last hole.

"But my birdie on three kind of turned the round around and making the string of (four consecutive) birdies definitely helped."

Ko won her first Major at last year's Evian Championship before adding a second at the ANA Inspiration in April.

"There's a lot of golf to be played, so I don't really want to get ahead of myself," she added.

Canadian world No. 2 Brooke Henderson (71) and fourth-ranked American Lexi Thompson (73), on the same flight as Ko, each ended the day at 147 to narrowly make the cut.

REUTERS

US WOMEN'S OPEN

Day 4: Singtel TV Ch115 & StarHub Ch209, tomorrow, 3am