Christy O'Connor is alone in second place after a 4-under-par 68 in the opening round at Crandon Park Golf Club.
Wadkins tallied two birdies and a bogey in his first three holes Friday and closed his front nine with a pair of birdies. He knocked a 4-iron to 10 feet to set up birdie at the seventh and dropped a 10-footer at the eighth to reach 3-under par for the round.
Wadkins looked in great shape at the start of his second nine. He landed in a bunker at the par-5 10th but blasted his third to a foot for a kick-in birdie. At the par-3 12th, Wadkins landed a 6-iron six feet from the hole to get sole possession of first at 5-under.
Then persistent back problems flared up on the 51-year-old Virginia native.
'I got back spasms after the 13th hole,' said Wadkins, who is the last player to win his first event on the Champions Tour when he titled at the Lightpath Long Island Classic in 2001. 'The back bothers me on chipping and putting. I'm okay swinging the club.'
At the par-4 14th, Wadkins laid up short with his second but played an 8-iron 20 feet short of the hole. He holed that birdie putt to get to minus-6 but trouble loomed.
Wadkins' tee shot at the par-3 17th bounced into a greenside bunker. He blasted out 10 feet past the hole but failed to convert the par-saving putt.
He rebounded at the last when he smoked a 3-wood on to the putting surface, 65 feet short of the hole. Wadkins had no real chance to make the eagle putt with a chunk of the fringe in his line, but he lagged it four feet left of the hole. He drained the birdie putt to get back to 6-under and earn sole possession of the first-round lead, a first since he joined the Champions Tour.
'The birdie at 18 was like a bonus,' said Wadkins, who finished 13th on the 2002 Champions Tour money list despite not winning a tournament. 'I'm very pleased, especially with the way I putted last week. Once I got it to 6-under, I knew I was in the ball game. I learned you need to be close after Friday.'
O'Connor, playing thanks to a sponsor's exemption, carded only one birdie on his front side Friday but made his run in a four-hole stretch on the back nine.
He holed a 10-foot birdie putt at the 13th and made it two in a row with a four-footer at No. 14. The Irishman hit a beautiful 7-iron to three feet at 16 to get to 4-under and reach second place.
'I'm trying not to put too much pressure on myself to win,' said O'Connor, who has been hampered with injuries over the last two years. 'I hope I don't give it away. I want someone to win it from me rather than give it away.'
Gary Koch, an NBC analyst who is making his Champions Tour debut this week, shot a 3-under 69 Friday to share third place with David Eger, Walter Morgan, Jerry McGee and Rodger Davis.
John Jacobs, the 2002 champion, is part of a group at 1-under par.
Fuzzy Zoeller, the 2002 Senior PGA Champion, was disqualified Friday thanks to a bizarre situation after the round. He was demonstrating proper swing technique for a local television report while hitting shots at the sixth hole.
That is a violation of Rule 7-1b, which states that when two or more rounds of a stroke competition are to be played over consecutive days, a competitor shall not practice between those rounds on any competition course remaining to be played.