Edward Loar, Alexandre Rocha, Jin Park and Kris Blanks were a stroke back. They also opened the six-round event on the Stadium Course.
Sweden's Robert Karlsson, an 11-time winner on the European Tour, shot a 66 on the Jack Nicklaus Tournament Course. Two-time heart transplant recipient Erik Compton had a 67 on the Stadium Course.
The top 25 and ties will receive 2013 PGA Tour cards and the next 50 and ties will earn Web.com Tour cards.