Lydia Ko not only became the first New Zealand amateur to make the cut at the women's US Open Championship after the 15-year-old carded an even par 72 today but she is also the leading amateur at the halfway mark of the prestigious competition.

The world No 1 amateur was in a share of 29th after today's second round, seven shots behind Norway's Suzann Pettersen, who holds a one-shot lead over Americans Michelle Wie and Cristie Kerr. Ko is two shots ahead of the next best amateur, Emma Talley of the US, and one of only three amateurs left in the field.

Ko, who is only the second New Zealand amateur to contest the US Open Championship after Olivia Hartley in 1999, met her goal of even par today and felt much more comfortable on the greens.

"It was much better today," said the youngest winner in professional golf history. "The first three holes [in round one], my hands were shaking I was so nervous and I was trying to line up my putts but I couldn't get it straight.


"I made a birdie on 11. I hit it to 12 feet past the hole, my putting was rolling well today. I made bogeys on 12 and 13 yesterday and was happy to make pars on both of them today.

"I made birdie on 15 and then double on 17 and it kind of went down but I made birdie on two and I was putting well then. I shot one under on the front nine which was my back nine so I was pretty happy."

At 6359m, Blackwolf Run is the longest course Ko has ever played in a tournament. She has been preparing for the length from the black tees of her new home course at Gulf Harbour.

"Gulf Harbour was playing 7000 yards [6400m] which was playing in a longer condition because it was wet. So I came prepared for that and expected that distance. It's a bit drier here which is helping.

"I think just playing along with the pros, that is a positive for me and I am here for experience - even if I come first or like top 10 I am not going to get any money so I am just playing here for fun and I'm going to enjoy every moment that I have.

"I am not going to be fully stressed about it. Hopefully I will be able to play with some great players and just enjoy it."

Ko still has her eyes on the top of the leaderboard but at the same time is monitoring the progress of her amateur competitors.

"There are many talented amateurs out there and they are going to try to their best as well we'll see how we go."