Defending champion and two-time 2001 winner Larry Nelson is one shot back after an opening 69. Hes in a tie for third with Vicente Fernandez and Jerry McGee.
Last years runner-up, Bruce Fleisher, is alone in seventh place at 2-under.
Canizares earned his maiden Senior PGA Tour victory earlier in the season at the Toshiba Senior Classic, where he beat Gil Morgan on the 9th hole of sudden death.
Like Ginn, the Spaniard recorded four birdies and no bogeys in the first round. Ginn did the majority of his scoring on the front nine, while Canizares did so on the back.
Starting at the 1st, Ginn made the turn in 3-under-par 33, and then added another birdie at the par-4 10th. He finished his day by parring his final eight holes.
Canizares, who began on the 10th hole, notched three birdies over his first nine holes, before playing his final nine in 1-under.
Baoicchis round was a bit more exciting. He made only three pars over his first ten holes. In that stretch, the South African made five birdies and two bogeys. Following a streak of seven straight pars, Baiocchi finished his round by birdieing the par-5 9th, his 18th hole of the day.
Full-field scores from the Las Vegas Senior Classic