Lydia Ko has had a mixed start to her first major of the year.

The world No 1 was one-under after her opening round at the Chevron Championship in Texas and was four shots off the leader among the morning starters, Taiwan’s Pei-Yun Chien.

Ko had a roller-coaster round including four birdies and three bogeys which left the New Zealander on 71 alongside Canada’s twice major winner Brook Henderson.

As she left the course after her opening round, Ko told NBC Sports that she had “struggled the first few times” she had played practice rounds there.

“I was like, I don’t know how I’m going to do this.

“But I feel like when you start playing, even if you don’t hit it the best you can, you can just manage your way around and not try to make it perfect, just try to shoot the best score.

“I think there were a lot of positives. I wasn’t the most confident going into today, so to start off like this, I think there’s a lot of good things to take.

“Hopefully I’m going to take all the good for the next few days and take the not-so-good stuff and polish it up a little bit.”

Chien seized early control of the year’s first women’s major in Texas, carding a five-under 67 to grab the first-round clubhouse lead and steal the spotlight from the sport’s big names.

Chien, the world’s 189th-ranked player, mixed six birdies with a single bogey at the Jack Nicklaus-designed The Club at Carlton Woods near Houston on Thursday to lead Americans Marina Alex, who shot 68, and Angel Yin another stroke back on 69.