Even a painful back isn't slowing Allen Doyle in his first full year on the Senior PGA Tour.

Using his unique slap shot-style swing, Doyle shot a 6-under-par 66 today and opened a four-shot lead over Lee Trevino after two rounds of the $1.1 million Cadillac NFL Golf Classic.

Bob Charles, Joe Inman and John Bland were another stroke back and one ahead of a group that included Dana Quigley, whose second-round 65 was the best score of the day on the Upper Montclair Country Club course.

The lead is the largest on the Senior PGA Tour heading into a final round this year and it puts Doyle within reach of his third title this year and $1 million in earnings.

Rookie Bruce Fleisher is the only three-time winner on tour this year, but winning the $180,000 top prize would make Doyle the first over the million mark.

"Allen Doyle is playing as good as anyone I've seen," said Trevino, who is looking for his first victory in 14 months. "I don't see how anyone is getting close to him this week."

What made Doyle's 11-under 133 total the more remarkable it that he has put it together despite being hampered by a bad back in both rounds.

"I'm a little bit surprised," Doyle said. "When I say I can play hurt, I can make pars. But in this game you have to make a shade better than par."

In building his lead, Doyle had gotten off to quick starts and then held on when his back started to spasm. It happened after No. 11 on Friday and No. 5 today.

Doyle's back actually started to bother him as he finished fourth in last week's event outside St. Louis. It started acting up again Friday when he shot a 67 to share the first-round lead with five others. The problem this week has been spasms instead of a dull pain like last week.

Doyle said he warmed up well and then got off to a quick start, making birdies on the first three holes to take a one-shot lead over Trevino, who also got off fast with two birdies.

However, Doyle aggravated his back again while making a birdie on No. 5 to go 9-under. He had to deal with spasms the rest of the way.

"He was in a lot of pain after that," said Erin Doyle, his daughter and caddie.

But never enough to stop him.

"I could crawl if I had to," said Allen Doyle, whose has seven top-10 finishes in 13 events this year. "I might shoot 80 tomorrow, but I'll finish. I'll never quit. I feel I can scratch out par. You've got to keep on going."

Doyle had eight birdies and two bogeys on his second trip around the tree-lined, 6,816-yard course that allows players to use a variety of shots.

The putter was Doyle's best weapon all day. He made birdies from 15, 12 and 10 feet on the first three holes and he added two 6-footers. The other three came on short putts on par-5 holes, two of which he reached with his second shot.

"Right now I'm hitting good irons and putting well," Doyle said. "I hope I'm not birdied out."

Trevino played the front nine in 4-under-par en route to a 70. The 59-year-old winner of 28 senior events was within a shot of Doyle most of the round until consecutive bogeys at Nos. 14 and 15.

Doyle's bogeys came with a three-putt from 18 feet on No. 6, the hole after he hurt his back, and at the par-3 17th when his tee shot went in a bunker.

In the NFL players' portion of this event, Tennessee kicker Al Del Greco shot a football players' record 3-under 69 to beat two-time defending champion Trent Dilfer, the Tampa Bay Bucs quarterback.

Del Greco, who has won this event five of the last seven years, bogeyed his first three holes and then made a 25-foot par saver the next hole. He played the final 14 holes in 6-under.

"This is my most satisfying win, especially because of the way I started," he said. "It was my dream to shoot a 69 and win. I didn't realize until I left the last two years how important it was to me."

Del Greco earned $30,000 and a Cadillac for his charity, the Del Greco Foundation.

AP