Top-ranked Lydia Ko shot a course-record and career-best 11-under 61 on Saturday to take the early second-round lead in the New Zealand Women's Open.

The 17-year-old New Zealander, coming off a victory Sunday in the Women's Australian Open, broke the Clearwater record of 63 set last year by Mi Hyang Lee in her victory.

Ko rebounded from an opening bogey with an eagle on the par-5 second and birdied Nos. 4-7, 9-13 and 18.

 ``I didn't know what I was shooting but when I went past the scoreboard on 13, I thought, `Oh, 59, that is the magical number.' But I'm pretty happy with 61,'' Ko said.

She had a 13-under 131 total.

 ``After the first, I was pretty angry. I got into the rough and it was pretty tough for the pin location. I left it short and that really made me angry as I did that yesterday and was not going to do it again today. The greens were much better today and rolling better and after that eagle I just got myself into the right position.''

England's Charley Hull was second at 10 under after a 64.

``Coming from Royal Melbourne last week the greens were so fast and really tricky. With these ones you can be a bit firmer and not allow so much break,'' Hull said. ``I think I had 26 putts. I hit some good putts out there, so I'm pretty happy with the way I played. You always believe you've left a few putts out there, but I holed a fair few as well. Going into the final day I think I'm in a good position.''

The tournament is sanctioned by the European and Australian tours. (AP)