Six birdies against a lone bogey on The Grange Golf Club’s West Course gave Webb a morning round of 5-under 67 to sit in equal second at day's end, two shots behind opening round leaders Jodie Ewart Shadoff and Wei-Ling Hsu.
Teeing off the 10th in a marquee group alongside defending champion Jin Young Ko and Women’s British Open champion Georgia Hall, Webb made a fast start with birdies at 13, 14, 16 and 17 to turn at 4 under.
After adding a fifth birdie at the par-5 opening hole, the veteran Queenslander dropped a shot at the par-4 6th but responded with a 15-foot birdie putt at the short 8th and a closing par.
"I hit some good shots and saw some putts go in, so I felt really comfortable there for about 11 holes," Webb said after her round.
"Then it got a little scratchy there through the middle, but I hung in there and managed to birdie the 8th.
"The swing didn't feel quite as good as it did early on, so happy to still shoot 1 under on the back nine."
The 44-year-old’s was the hottest group of the morning wave with playing partners Ko and Hall signing for 68 and 69 respectively.
Webb’s 67 was matched by Swede Madelene Sagstrom and England's Bronte Law while her compatriot Ewart and Chinese Taipei's Hsu were in a class of their own.
31-year-old Ewart was bogey-free in her 65, carding 7 birdies between and the 1st and 13th holes while Hsu needed 8 birdies for her 65.
Ewart – runner-up at the 2017 Women’s British Open – and 24-year-old Hsu are both chasing a breakthrough victory on the LPGA Tour.
"I think this probably is my best round in an Aussie Open," said Ewart, who finished 20th the last time The Grange hosted the Women's Australian Open in 2016.
"I actually really love this course. I've played it a few times, and I really enjoy playing here."
Australia's top ranked player Minjee Lee - chasing her maiden national title - opened with a 71.
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