Thorpe, also the 2003 winner at Sonoma Golf Club, took the last spot in the field Sunday, edging Tom Jenkins by $4,079 for 30th place on the money list.
'I'm just happy to be here,' Thorpe said. 'It hasn't been a stellar year. Getting here was more difficult than winning a golf tournament. You can control what you are doing, but not what others are doing.'
Playing by himself after Mark O'Meara skipped the event, Thorpe shot a 6-under 30 on the back nine. He birdied Nos. 10-11 and 13-14, dropped a stroke on 15, then birdied the final three in a round that took only 2 hours, 35 minutes.
'The pace of play was perfect for me,' Thorpe said. 'I didn't have to hear anyone complain the whole day. It was perfect.'
Romero, the Argentine star who won the 2006 JELD-WEN Tradition, also had nine birdies and a bogey. He made five straight birdies on Nos. 12-16.
'I'm playing fantastic. My game is good,' Romero said. 'It's been good all year long.'
Romero needed only 23 putts, a half-dozen less than normal.
'Twenty-three putts?' Romero said. 'If I could do that every round, I'd always shoot 62, 63 or 64. I'm happy with my game. I played a fantastic round.'
Mark James was two back strokes at 66, D.A. Weibring had a 67, and Jay Haas was another shot behind along with Tom Purtzer and Brad Bryant.
Loren Roberts, 165 points ahead of second-place Haas in the Charles Schwab Cup competition for a $1 million annuity, opened with a 71.
Last year, Roberts missed a 4 1/2 -foot putt on the final hole to give Haas the points title. The tournament winner this week will receive 880 points.
Bryant and Tom Watson also are still alive in the points chase. Tom Watson, 694 points behind Roberts, shot a 74. He has won the tournament three times.
Bryant entered the week 697 points behind Roberts.