Barnard, who began her round on the back nine of the Royal Pines Resort, followed an opening par with four straight birdies from the 11th through the 14th. Although a bogey at the 18th dropped her back to 3-under at the turn, Barnard responded with four more birdies on the back side to climb to the top of the leaderboard.
'I've played in this event seven times before and I've never putted very well on these greens, but today I putted very well,' Barnard said. 'I got off to a great start, rolled in a few putts and got a good feel for the pace of the greens.'
Barnard lost her LPGA Tour playing privileges after spending the last three seasons on tour in the U.S. This season she will compete on the Ladies European Tour, where she has been a member since 1984.
While Brooky's lone bogey came when she three-putted from 20 feet at the 10th, world No. 1 Webb managed to make it through her round of 5-under 67 without dropping a stroke.
'I had a little streak, making four consecutive birdies from 14 to 17, and I supposed it dried up a little after that,' said Webb, who also started at the 10th hole on Thursday.
Webb is looking to become the first woman since Laura Davies to capture the same event four years in a row. Davies won the LPGA Tour's Standard Register Ping from 1994-97.
Webb, who won her first four starts last year, is still in search of her first victory of the 2001 season. The 26-year-old Australian has finished second twice.
Sweden's Gustafson, who posted a win at the LPGA's Memorial of Naples event in January, turned in a card with six birdies and one bogey, as did Marshall of Scotland.