Tom Watson and Bruce Fleisher share third place one shot back at minus-6. Vicente Fernandez and Jim Holtgrieve are tied for fifth at 5-under-par 65.
Low scores were the norm on this day as the field recorded the lowest scoring average for a first round in Champions Tour history. The 81-player field turned in an average 69.00, breaking the previous opening-round mark of 69.39 set at last year's RJR Championship.
Thompson's and Morgan's bogey-free rounds mirrored each other. Both men posted three birdies on the front nine and four on the back side.
Thompson, who holds a share of the first round lead for the first time since the 2000 BellSouth Senior Classic, got going with back-to-back birdies from the second. After a string of pars, the three-time winner on the Champions Tour rolled in a 10-foot birdie putt at the par-5 seventh.
'I knew someone was going deep at the start,' said Thompson. 'I made birdie on two of the first three holes and then didn't make another birdie until seven. I thought I was behind.'
On the back side, Thompson recorded consecutive birdies from the 10th both from inside 10 feet. He later birdied the par-4 13th and closed out his round with a 15-footer for birdie at the par-4 18th.
'I played well today,' said Thompson. 'I did everything real solid. I don't usually shoot 63 unless I play well. I had lots of makeable putts today.'
Morgan, the 2000 winner of this event, notched birdies at each of the first two holes. He later rolled in a four-footer for birdie at the par-4 fifth.
Morgan, the reigning BellSouth Senior Classic champion, carded two more sets of consecutive birdies on the back nine. He started with a birdie at the par-4 10th and followed that with another one from four feet at the par-5 11th. Morgan notched his final birdies of the round at Nos. 14 and 15 both from 10 feet out.
'Today was an excellent day for scoring,' said Morgan. 'I am pleased with my position. I am confident on this course with my past success here. This is one of my best rounds on this course.'
Watson held the lead by himself at one point, but struggled down the stretch. He carded birdies at Nos. 5, 7 and 9 on the front side and around the turn, Watson caught fire early. He rolled off five straight birdies from the 11th, longest from 16 feet out, to climb to minus-8.
'I was off to the races starting at No. 11,' said Watson of his five straight birdies that tied Bob Eastwood for the best such stretch on the Champions Tour this season. 'I was in a zone for a little while. Today was a day for scoring.'
However, Watson bogeyed the final two holes to fall one stroke behind the leaders.
'I didn't finish very well. Dinner won't taste very good,' Watson said of his late bogeys. 'I had 60 or 61 in my sights. But I'm not crying too much.'
Defending champion Dave Eichelberger struggled to a 4-over-par 74.