Amateur In-Bee Park, who was the runner-up at the 2003 U.S. Girls' Junior, shot a 6-under-par 66 and is tied for third place with Nicole Perrot, Wendy Doolan, Catriona Matthew and Mi Hyun Kim at Las Vegas Country Club.
Park tied for seventh last year in Vegas and the high-school junior believes she can win.
'If I play like this tomorrow and the day after, I'm sure I can,' said the 16-year-old Park. 'I have nothing to lose. I just come out here and have fun. The pressure is on them actually because I'm only 16.'
Webb, who defeated Annika Sorenstam in a playoff at the first staging of this event in 2000, opened on the back nine Thursday and got off to a horrible start. She came up short of the green with her second at the par-5 10th, but chipped to 30 feet. Webb three-putted for an opening bogey.
She calmed down after the miscue at 10 with a 25-foot birdie putt at the 13th. Webb hit a 7-iron to 8 feet to set up his second birdie in a row at 14, then knocked a 7-iron to 20 feet for another birdie at the 16th.
On the second nine, Webb wasted little time in getting into red figures. She played a sand-wedge to 5 feet at the first, then collected her second birdie on the nine at No. 4.
Webb's second at the par-5 sixth fell short of the putting surface, but she chipped up to a foot and tapped in for birdie. She closed her round with back-to-back birdies from 15 feet and 5 feet, respectively.
'I was just trying to hit good golf shots instead of just trying to work on things,' said Webb. 'The biggest thing that happened today is I made some putts.'
Webb was once the top player in women's golf until Sorenstam jumped to the top. Webb has only two wins in the last two seasons, but the Australian believes she is ready to resume her spot atop the LPGA Tour.
'I'm really, really close,' said Webb. 'Obviously shooting 65 today gives me a load of confidence. I'm really good on the range and I'm just not taking it back to the course every day. I think I could be better than I was. That's why I made changes.'
Ward kicked off her round with an 8-footer for birdie at the first. Two holes later, Ward drained a 12-foot birdie try, then ran off three birdies in a four-hole span to close her front nine.
Ward used sensational wedge play to climb up the leaderboard. At the 11th, Ward hit a 58-degree wedge to tap-in range, at the 12th it was a 52-degree wedge to 8 feet and on 13 it was the same club to 10 feet.
The American was 8 under par for her round until she came to the 15th hole. Ward drove right into the trees and was forced to punch back into the fairway. She chipped to the fringe and two-putted for a bogey that dropped her down to minus-7.
'The neat thing about this course is that pretty much every hole is birdieable,' said Ward. 'One thing that I work hard on is to not put too much pressure on myself or get too disappointed when you miss a birdie opportunity. You know there is going to be another one facing you right on the next hole.'
Aree Song shot a 5-under 67 and shares eighth place with Sophie Gustafson and Mikaela Parmlid.
Defending champion Cristie Kerr opened with an even-par 72.