The tournament is an official Senior PGA Tour event for the first time, with the Legends Division switching from a team format to individual play. The tournament was first play in 1978, sparking interest that led to the creation of the senior tour in 1980.
Dougherty, battling a cold and dizziness, was 2 under through 12 holes and added birdies on Nos. 13, 15, 17 and 18 on The King & Bear Course at the World Golf Village.
'I felt dizzy out there, my eyes hurt, I'm sure I've got a cold,' he stated. ``I had my caddie read all my putts today. He did a good job.
That included a 50-foot birdie putt on the second hole that got Dougherty off to a good start. He hit a 3-wood to the green on the par-5 13th and two-putted for birdie, and closed with 20- and 25-foot birdie putts on Nos. 17 and 18.
'I really putted well, plus I really drove the ball well,' he said. 'You have to drive the ball well if you want to attack this golf course. If you're in the rough, you're in trouble because of the pin placements.
'I played pretty well last week, especially in the final round at Pensacola. Even though it got washed out due to rain, it gave me a lot of confidence coming into this event.'
Irwin, who has a senior-record 34 victories, had his lone bogey of the round on No. 17, but rebounded with a birdie on No. 18.
Allen Doyle, Wayne Levi, Jim Dent, Vicente Fernandez, Tom Wargo and Bob Gilder opened with 68s.
Bruce Lietzke and Bill Rogers combined for a 63 and a three-shot lead over Chi Chi Rodriguez and Harold Henning in the 36-hole Raphael Division (50-69 years old).
Full-field scores from the Liberty Mutual Legends of Golf