The Royal Pines resort course, already saturated by four days of rain, received a further 1.7 inches in just 15 minutes Wednesday, causing officials to declare the course would be unplayable by the scheduled start of play at 6:30 a.m. Thursday.
'A cut will be made after 36 holes Saturday, with the top 65 and ties to play the final round Sunday,' tournament spokesman Brendan Moloney said.
More than 16 inches fell before Wednesday's downpour, meaning no practice rounds could be played on Monday or Tuesday.
The pro-am Wednesday nearly dodged the downpour. The morning group played under cloudy skies, but golfers in the afternoon grouping were called off the course with about three holes to play when a fierce thunderstorm hit the area.
The washout delayed the continuation of a rivalry between Australia's Karrie Webb and Shin Ji-Yai of South Korea.
Last year, Webb needed a course-record 62 on the weekend to put her in position for a two-stroke win over Shin at Royal Pines. Last week at Kingston Heath in Melbourne, Webb beat Shin on the second hole of a playoff to win her fourth Australian Open.
Ai Miyazato, Japan's top golfer, and three-time Australian Masters champion Laura Davies of England will also be leading contenders.
The 20-year-old Shin is ranked No. 7 -- the highest international ranking of any South Korean player, and she doesn't play on the LPGA Tour. There are 45 South Koreans playing on the LPGA Tour this season -- out of 121 international players -- and 33 South Koreans are ranked in the top 100.
'She's definitely got the talent,' Webb said of Shin. 'Obviously she showed that by how impressive she played last week. Shooting 67 on Sunday was no mean feat on that golf course.'
Webb shot 67 as well, making birdies on 16 and 17 when Shin was already in the clubhouse two strokes clear of the Australian.
'As far as finishes go, it hasn't been too many (tournaments) that I have played that I have looked at the leaderboard and known that I have got not that many holes left and still need to pick up a couple of shots,' Webb said.
'That was the most exciting thing for me -- I was able to switch it on when I needed to and make those couple of birdies.'
Webb has won the Masters seven times at Royal Pines -- four in a row from 1998 to 2001, in 2005 and last year.
The Australian says she's relaxed after an eight-week break before last week's Australian Open.
In 2006, Webb had five wins in 21 tournaments in a renaissance year, including 13 top 10 finishes. Last year, her best finish was a second place -- at the LPGA Championship -- and she had just six top 10s in 21 events.
'It was easy to enjoy good golf, not so easy to enjoy bad golf,' Webb said. 'It just got frustrating, and the more I felt I was close and the results were not coming, the more you want to see the results. By the end of the year, I was just really tired of beating myself up and worn down from that.'
She never thought of retirement.
'I want to play for another five or six years at least,' Webb said. 'I wouldn't do it if I wasn't enjoying it and I wasn't enjoying it last year. So I've just got to change a few ways and try to be less of a perfectionist.'
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