Amateur star Rose Zhang got off to a solid start in her highly anticipated pro golf debut on Thursday but it was Lauren Hartlage in the lead at the US LPGA Mizuho Americas Open.

Zhang, the top-ranked woman amateur and a two-time US collegiate individual champion, was in the spotlight in her pro debut at Liberty National in Jersey City, New Jersey.

The 20-year-old Californian fired five birdies and three bogeys in her two-under-par 70, which put her five shots behind first-round leader Hartlage.

India's Aditi Ashok was two off the lead after a bogey-free five-under-par 67.

Thailand's Atthaya Thitikul and Northern Ireland's Stephanie Meadow shared third on 68 and world number three Lydia Ko headlined a big group on 69.

"It was amazing," Zhang said. "It felt pretty regular throughout the round once I got into the zone.

"But the anticipation was for sure there. I feel like there has been a lot of things happening the last couple days and last couple weeks, so for me to come out here and just try to stay composed, I feel like I did a pretty good job at it."

Zhang's round included a chip-in birdie at the par-five 13th. That was followed by back-to-back bogeys, but she capped her round with another birdie at 18.

"Definitely a lot of flavor there," she said. "That chip-in was just amazing. Gave me a little bit of adrenaline going into the next couple holes, and found out I had a couple putter yips.

"But, you know, I made it back. Had 17 and 18 as really solid putts and kind of got my groove back."

Hartlage got off to a hot start with an eagle at her opening hole, the par-five 10th.

"Hit it to a foot and tapped in for eagle, so getting off to a really good start always helps," said the 25-year-old who is chasing a first LPGA title in her second season on the tour.

"I was just hitting my driver great," said Hartlage, who added five birdies. "I think I hit almost every fairway, and out here getting yourself in a good position, the greens are pretty receptive, so it's getting yourself in the fairway, and I gave myself a lot of good birdie chances."

Hartlage was delighted to have turned things around after going 0-3 at the LPGA Match-Play in Las Vegas last week.

"I feel like no one really expects me to be at the top, and it's kind of fun just being able to just play with some of the best in the world and see how I rank," she said.

Ashok, who lost in a playoff at the LA Championship in April and finished tied for fifth at the Founders Cup, said she's got confidence that she has the game to eventually get to the winner's circle.

"I don't think you can ever go into an event thinking this is the one I'm going to win because golf kind of humbles you sometimes," she said. "But I just know that if I play good four days, then I'll have a pretty good chance.