Atwal, who came through as seventh in second stage, will now find things tough in the Final Stage as he tries to overcome his rough start at PGA West Stadium course.
Meanwhile, Daniel Chopra had a decent start at four-under 68. Playing at the same course PGA West, Chopra bogeyed the third, but then found five birdies and no more bogeys for a good start.
In tied 50th place was Bhavik Patel, an American of Indian origin, who shot two-under 70.
Atwal had five pars before his first bogey on sixth, but he recovered with a birdie on eighth. A birdie on12th augured well before he bogeyed the 16th and double bogeyed the par-4 18th.
Steve LeBrun put himself in good shape with an opening-round 64 on the Stadium Course to take a one-shot lead after the first round.
Only the top 25 (and ties) after six rounds will receive PGA TOUR cards for 2013 with the rest earning Web.Com Tour status or conditional status on that tour.
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LeBrun was flawless, making eight birdies and no bogeys on the typically more difficult of the two courses. Among the four players tied for a second is Kris Blanks, who despite nagging injuries since mid-summer managed to be mistake-free.
Jin Park, Alexandre Rocha and Edward Loar are also at seven-under 65, while Robert Karlsson is among those at six-under 66.