Playing on a course where he won the Texas Open 17 years ago, O'Meara fired a 29 on the back nine, which included an eagle on the par-5 15th.
Champions Tour newcomer John Cook, who turned 50 Oct. 7, shared second place with Wayne Levi. Tied for fourth at 66 were Fred Funk, Craig Stadler, Tom Purtzer and Tom Kite -- who in a 35-year professional career has never won in Texas, his native state.
There were 36 sub-par scores recorded at the Oak Hills Country Club course, which has been home to the Texas Open 23 times. In addition to O'Meara, Arnold Palmer, Lee Trevino, Ben Crenshaw, Nick Price and former PGA Tour commissioner Deane Beman recorded victories at Oak Hills.
Crenshaw was one of those breaking par Friday with a 1-under 70.