(Reuters) - Lydia Ko carded a blemish-free seven-under-par 65 on Friday to take a one-stroke lead at the LPGA KEB Hana Bank Championship in South Korea and boost her chances of usurping Park In-bee at the top of the women's world rankings.
The 18-year-old New Zealander, the youngest woman to win a major, trailed overnight leader Park Sung-hyun by seven strokes at the start of the second round but finished on 10-under, ahead of American Lexi Thompson (67).
"When a player shoots 10-under, seven-under, eight-under, whatever, they had a great day and all you can do is play good golf yourself and just think about it one shot at a time and see the closer you are to the leader, or if you're leading, the earlier, the better," she told reporters in Incheon.
"Because if you are leading, you've got time where you can expand the lead and give yourself a little bit of breathing room.
"I put myself in good position but the weekend is where they say people try to go up the leaderboard. I'm just going to focus on one shot at a time and on my game, because I know there's going to be a lot of great golf from a lot of great players."
Ko was in the same playing group as Park In-bee, who is tied for 25th place at three-under, and could reclaim the top ranking from her South Korean rival with a victory this week after two wins and a runner-up finish in her last three starts.
"I don't think about the rankings or if one birdie is going to put me a couple shots in front of her," said Ko, who claimed her maiden major title at The Evian Championship in France last month.
"I feel very fortunate that there is a great competitor like her where I can work harder and be as good as her or get to that ranking.
"But when we're out there, we are not thinking about it. I think for the crowds and for the media, it makes it really exciting when everything is close."
First-round leader Park Sung-hyun struggled in the second round and frittered away her four-shot lead by posting a 74 for a share of third-place alongside Cho Yoon-ji at eight-under.
Reporting by Sudipto Ganguly in Mumbai; Editing by John O'Brien