Tammie Green notched a 3-under-par 67 to stand alone in third place. Green is followed by Young-A Yang, Dorothy Delasin and Cristie Kerr, who are tied at minus-2.
Webb had a very steady round before closing with a bang. She got on the board when she sank an 18-foot birdie putt at the par-4 fifth. The Australian then posted nine consecutive pars.
'I got off to a pretty slow start,' Webb said. 'I played pretty sketchy on the front nine, but managed to make one birdie and actually got up-and-down a couple of times.'
Down the stretch, Webb was zoned in. She dropped a wedge within 12 feet for birdie at the 15th. Her third to the par-5 16th came to rest about the same distance away and she made it two in a row when that putt dropped.
Webb, who owns 28 career LPGA Tour titles, stuck her 8-iron 12 feet from the cup on the 17th to make it three straight. At the last, she hit the same club onto the green and sank that putt to close with four straight birdies.
'I just wasn't hitting it real close until the last four holes,' Webb said. 'I hit it inside 15 feet really. I at least had a couple of chances and made the most of them and made some birdies coming in.'
Andrews seemed to be in control early on, but her late struggles cost her the overnight lead. Andrews opened with three consecutive birdies. At the first, she rolled home an eight-foot birdie, before sinking a 24-footer at the next. She dropped her third shot to the par-5 third within two feet for a kick-in birdie.
Andrews had a similar run later on the front side. She rolled home a 15-footer for birdie at the par-3 fifth and followed by draining a 24-foot birdie try at the next. She capped this run of three straight by chipping in from over the green on the seventh.
Her momentum ended quickly though. She missed the green at the par-4 eighth and was unable to get up-and-down for par. Around the turn, Andrews' struggles continued. She bogeyed the par-4 12th and three-putted for bogey at the 15th.
She was able to come back with a birdie at the last when her pitching-wedge stopped within one foot of the cup.
'Unfortunately having shot a 62 here two years ago, everybody was reminding me of it,' said Andrews. 'With the gallery cheering for me and saying things like 'Just like last time,' it was hard not to think about.'
Andrews has been battling back problems the last several weeks and they continued Friday.
'I have not played that much in the last six weeks and hit mainly three- quarter shots today to keep my back feeling good,' Andrews said. 'It still gives me a little trouble if I am standing downhill.'
Defending champion Annika Sorenstam, who returned to action for the first time since winning the Women's British Open early in August, carded a 1-under-par 69. She made the turn at 1-over, but ran off four consecutive birdies to climb to 2-under. Her run ended with a bogey on No. 16 that dropped her in to a tie for seventh.
Sorenstam is joined at minus-1 by Karen Pearce, Stacy Prammanasudh, Karen Stupples, Rachel Teske, Dawn Coe-Jones, Penny Hammel, Loraine Lambert, Mardi Lunn, Jill McGill and Gloria Park.