Leona Maguire ended the day tied for fifth with amateur sensation Áine Donegan tied for 11th as Pebble Beach bared its fangs in the second round of the US Women's Open.

Maguire was outside the top 10 after she struggled home in 40 and shot a two-over 74 to slip back to one-under-par and six shots behind the surprise leader, American rookie and qualifier Bailey Tardy.

But as the temperature dropped and the wind got up for the afternoon starters, Maguire goes into the weekend with just four players ahead of her as she bids to become the first Irish woman to win a major.

In an added boost for Irish golf, Lahinch's Donegan (21) proved a breath of fresh air for the championship as she played the first six holes in one-under and followed five bogeys in an eight-hole stretch mid-round with three gutsy closing pars for a 76 that leaves her as the leading amateur on one-under, tied with the likes of new US superstar Rose Zhang.

Tardy's four-under 68 in the first group of the day gave her a two-stroke lead over Hawaii's Allisen Corpuz (70) and Korea's Hyo Joo Kim (70).

Another Korean, rookie Hae Ran Rae, sits alone in fourth on three-under after a 72.

Then comes the determined Maguire, tied for fifth alongside Japan's Nasa Hataoka as the only other players in red figures and arguably the two favourites entering the last two rounds.

"Yeah, struggled a bit today," said Maguire, who missed eight greens in regulation as she followed birdies at the 17th and 18th with bogeys and the first, second, third and fifth before following a birdie from 20 feet at the sixth with a three-putt bogey at the ninth.

"I had a lot of really good up-and-downs to keep me in it, but I didn't really play my best golf today. Didn't hit enough greens, and that made things a little bit difficult."

She added: "It definitely played harder today, I would say, than yesterday. There's a few of the pins where the wind is blowing and you just can't really get at them."

With the scoring only getting tougher as the day wore on in winds gusting to 27 mph, her 74 turned out to be a fine score.

“Just need to hit more greens, I think," Maguire said. "It's really tricky around these greens if you start missing greens, so I just need to hit a few more greens and give myself a few more chances."

She paid little attention to the leaderboard, knowing a red number beside her name was positive.

"No, under par around here, you always know you're going to be in good shape," she said. "Just made a few bad swings and kind of cost me, that early stretch on the front nine."

Donegan dropped an early shot at the second when she failed to make a big carry and had to take a drop from an unplayable lie.

But she recovered with birdies from around five feet at the third and sixth, bogeyed the eighth after a poor approach and then did a live walk-and-talk for TV on the ninth that resulted in worldwide exposure for Lahinch.

As a qualifier, Donegan has captured the imagination of the US media with her sunny, down-to-earth disposition and her tales of woe en route to the west coast.

It took her and coach-caddie Gary Madden 30 hours to make it from the Vagliano Trophy in Scotland to San Francisco and while her clubs arrived late and she was forced to add a new driver to her bag after hers was smashed in transit, she's bombed the ball off the tee and played some tremendous golf as she bids to become the first amateur to win a women's Major since Catherine Lacoste won the US women's Open at Atlantic City Country Club in 1965.

"I started with a bogey on the second, the par-5," said Donegan, who had an inspirational chat with Lacoste this week. "I went for it in two and it didn't work out. I had to take an unplayable drop, but luckily I bounced back straight away with a birdie.

"Then birdied six, made a nice four-footer, four- or five-footer for that, and then I had two sloppy bogeys on 8 and 9 from the middle of the fairway on both.

"I hit a really, really bad shot on eight into the right front bunker and just missed an eight-footer for par. And then 9 I three-putted. It was a long putt. My second shot was probably the problem on nine, but then I three-putted, which was disappointing.

"Then the back nine was playing so tough. My playing partners struggled there, as well, and I'm sure everybody else is struggling a little bit on the back nine.

"It's getting cold now. The wind is picking up and the greens are really firm, way firmer than the front nine and even yesterday.

"I'm not sure, I haven't looked at the leaderboard, but I'd say if you were to look at a leaderboard the better scores would be from this morning."

Despite those bogeys at the eighth, ninth, 12th, 13th and 15th, Donegan is still very much in the hunt but also thoroughly enjoying her week, even if making the cut means she misses next week's European Amateur Team Championships in Finland.

"I'm pleased with how I finished," she said. "I finished with three pars and that was my goal, just try and get in with the same score, and luckily I did."

Supported by family, she will have even more fans at the weekend as pals travel to Pebble Beach to watch her take on the best players in the world.

"Well, me and my family, we all can't really believe it to be honest," said Donegan, who will begin her junior year as a golf scholarship student at Louisiana State University in the autumn.

"We made the main news channel in Ireland, which is like a big deal, which was cool, and then actually one of my best friends here, I've known here since I was about four years old, and she was just over in the States at her aunt's house in San Francisco with her dad and a few of her siblings, and they extended their flights to stay for this, so she's been here the first two days, and I actually think they extended their flights again until the end of this.

"Then two of my best friends are up in Vancouver for the summer, and they booked flights to come down, as well, for the weekend, so it's going to be really nice to see some familiar faces.

"Even the faces that aren't so familiar, there's a lot of Irish people out here supporting and stuff, which is really nice. I'm having a great time."