K.J. Choi stands alone in third place at 7-under-par 65. Australian Richard Green is one stroke further back at minus-6. He was joined there by Tony Carolan and Jean Van de Velde.
Scott, who won this event last year when it was played at Pine Valley Golf Resort and Country Club in Beijing, China, opened with a birdie on the first. He faltered to a bogey on two, but came right back to birdie the third.
The Australian drained an eagle on the par-5 sixth to get to 3 under. Scott then converted back-to-back birdies from the eighth. He picked up another birdie on the 11th at The Vines Resort & Country Club to get to 6 under.
Scott stumbled to the second bogey of this round on the par-4 14th. He got that stroke back at the 16th. The 25-year-old made it two straight with a birdie on the 17th. Scott two-putted for birdie, from 10 feet away, at the par-5 closing hole to join Stadler atop the leaderboard.
'It was a good first round. Three birdies to finish is always nice,' said Scott. 'The wind got up a little bit, but it was a lot less than I was expecting. I was expecting it would be tough today. There is still a long way to go, but certainly it would be good to capitalize on this round tomorrow with another good one. Hopefully I can go out and keep making birdies.'
Stadler, playing on a sponsor's invitation this week, was steady to start his round with two birdies over his opening eight holes. However, at the ninth, he really turned things on to go flying up the leaderboard.
The 26-year-old sank a birdie putt on the ninth to make the turn at 3 under. Stadler then birdied the par-5 10th. He kept rolling with a birdie on the 11th.
Stadler moved to minus-6 as he converted a birdie on the 12th. He made it five straight as his birdie effort on the par-3 13th found the bottom of the cup. Stadler's birdie run was capped at the 14th when his birdie putt dropped into the hole.
He briefly moved to 9 under with a birdie on the 16th. Stadler, however, tripped to a bogey at the next to slip back to 8 under.
'I putted as good as I have in two years today,' said Stadler. 'I felt really comfortable on the greens. I'm driving it better, but I've been driving it pretty poorly the last year or so. The last six or eight weeks though it's been coming around.'
A quartet of Australians - Nick O'Hern, Ewan Porter, Brett Rumford and Marcus Fraser - share seventh place after shooting 5-under-par 67. Paul Casey, Craig Parry, Christian Cevaer, Terry Pilkadaris, Peter Senior, Bradley Iles and Shiv Kapur.
Other big names in the field include - Robert Allenby (minus-3), Colin Montgomerie (minus-2), Fred Couples (minus-1), while a pair of U.S. Open champions -- Michael Campbell and Retief Goosen -- are tied for 67th at even-par 72.