Neumann carded eight birdies and two bogeys at Highland Meadows Golf Club and leads three players by three shots. It's the 17th first-round lead of her 18-year LPGA Tour career, but just her fifth in the last nine seasons.
Reilley Rankin, Michelle Estill and Sung Ah Yim shot 5-under-par 66s to share second place. Six players -- including Paula Creamer, Natalie Gulbis and Laura Davies -- are tied one shot further back in fifth.
World No. 1 Annika Sorenstam is four strokes off the pace after opening with a 2-under 69. Sorenstam carded birdies at the par-3 eighth and par-4 16th and filled the remainder of her scorecard with 16 pars.
Neumann began her round on the back nine and made birdies at the 11th, 12th and 14th holes. She bogeyed the par-4 16th after chunking an 8-iron, but got that shot back with a birdie at the 17th.
On the front nine, Neumann carded back-to-back birdies at the first and second holes. She added another birdie at the fourth, made bogey from a wet bunker at the par-5 seventh, then ended her round with a birdie at the ninth.
'I was very solid off the tee today. I only missed one fairway and putted great,' said Neumann. 'Overall, I'm very happy with the round.'
In addition to hitting 12 fairways, Neumann found 16 greens in regulation and putted 28 times. The last time she won a tournament she led after 18 holes was at the 1997 Ping Welch's Championship.
Rankin opened her round with a birdie at the first hole, collected another birdie at the fourth, then gave a shot back with a bogey at the par-3 sixth.
She made the turn at minus-3, however, after holing out for an eagle from the fairway at the par-4 ninth. Rankin switched from a 7-iron to an 8-iron at the last minute and gripped down on the club.
'I hit the 8-iron very well, and I was right on line, and I just heard it hit the flag,' said Rankin. 'Then you can't see. It's kind of a blind shot, and the gallery kind of went crazy. It was fun. But we still had nine more holes to play.'
Rankin played the remaining nine holes bogey-free with birdies at the 13th and 17th holes. She has been competing with borrowed clubs since hers were lost by an airline on June 30th.
'I just tried to turn it all around and do a positive. I think it's all about attitude,' Rankin said. 'But obviously clubs make a big difference.'
Estill began her round on the back nine and opened with a birdie at the 10th. She carded consecutive birdies at the 14th and 15th, then gave a shot back at 16 after she drove her tee shot into the trees.
Three more birdies on the front nine -- at two, six and eight -- moved Estill to minus-5. She finished her round needing just 26 putts.
'Overall it was just a solid round,' said Estill. 'I made the putts when I wanted to.'
Yim opened with a birdie at the first hole and later completed the back nine with three straight birdies from the seventh. She stumbled to her only bogey at the 13th, then carded birdies at the 14th and 17th holes to get to 5 under.
The course was saturated after several inches of rain fell on Wednesday, and the round was delayed at the start because of the inclement weather.