Webb, who came from seven strokes behind Saturday with a 10-under 62 to share the third-round lead with fellow Australian Michelle Ellis, again made clutch putts to follow last week's six-stroke win at the Australian Open with her sixth Australian Masters title.
Her four-round total of 19-under 269 came despite bogeys on 17 and 18 that made the win look closer than it was -- she led for most of the back nine by four strokes.
'The 62 yesterday obviously really set me up for today,' Webb said. 'I got off to a flyer today, then did what I had to do on the back nine, which was nothing special.'
Shin Ji-yai of South Korea was second after a 69, followed by Cristie Kerr of the United States another stroke back after a 68.
Kerr had all four rounds in the 60s and did not make a bogey in 72 holes at Royal Pines this week.
'That's a first for me,' Kerr said of her bogey-free performance. 'She (Webb) shot 10-under par to put herself ahead of the field yesterday and that's what you are going to have to do if you're going to win against this kind of quality field.'
Ahn Sun-ju of South Korea, who led after each of the first two rounds, birdied the last for a 70 and finished fourth. Taiwan's Tseng Ya-ni, a former amateur playing in only her second professional tournament, had a 66 to finish fifth.
Ellis finished tied for sixth after a 75. She moved out of contention when she double bogeyed the par-4 eighth after hitting her tee shot out of bounds.
Webb took a four-stroke lead on the ninth hole with a 20-foot eagle putt that all but finished off her pursuers, giving her a 6-under 31 total on the front nine.
She lost a stroke in unusual circumstances on the 10th hole after picking up her ball and cleaning it when she thought it was on the green. After she realized her mistake, she called over rules official Graham Nightingale and gave herself a one-stroke penalty.
It was Webb's first bogey in 33 holes.
That reduced her lead to three over Shin, and Webb made a four-footer for par on the next hole. However, Webb's lead went back to four moments later when Shin bogeyed after hitting her tee shot in the bunker on the par-3 11th.
Webb, who is scheduled to make her 2007 LPGA debut next week in the SBS Open at Turtle Bay in Kahuku, Hawaii, held at least a four-stroke lead through the remaining holes until she bogeyed the last two.
Brittany Lincicombe had a triple-bogey on the par-3 11th when she went into the water, and finished tied for 13th after a 73. Lincicombe made up for the triple with a birdie and eagle on the next two holes.
Fellow American Natalie Gulbis shot a 70 to finish at even-par 288 and tied for 53rd.
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