Woods was at 13-under 127, his best start to a tournament since he was 15-under through 36 holes at Firestone in 2000, which he went on to win by 11 shots.
Austin had his second straight 65 and will play in the final group with Woods.
Woods' string of birdies, which included a bunker shot he holed from 60 feet on No. 5, filled East Lake in Atlanta with plenty of electricity. But it might have taken all the drama out of the FedEx Cup finale.
Woods is atop the playoff standings, a victory would give him the cup and the $10 million prize. Steve Stricker, who needs to win to capture the cup, shot 67 and was nine shots behind. Phil Mickelson, who can claim the FedEx Cup only if he wins the Tour Championship and Woods finishes worse than second, was seven shots behind after a 66.
Only a half-dozen players were within five shots of Woods, who hasn't lost a 36-hole lead in 3 years.
In other tournaments:
* At Halmstad, Sweden, the United States took a 4 1/2-3 1/2 lead over Europe in the Solheim Cup, despite a remarkable series of shots by England's Laura Davies to win the par-3 16th hole that included 50-foot chip shot into the cup.
* At Conover, N.C., Rod Spittle was 3-under through five holes when heavy rain forced Champions Tour officials to suspend first-round play in the Greater Hickory Classic. *