CHICAGO (Ticker) -- Threes were wild for Bob Gilder.

Gilder carded a 3 on each of the final seven holes Saturday, finishing with a course-record 9-under-par 63 and taking a one-stroke lead into the final round of the SBC Senior Open.

Gilder's lowest score on the elder circuit set the mark for the Port course at Harborside International. After making three birdies on the front nine, he went birdie-par-birdie-par-birdie-birdie-eagle coming in.

The fantastic finish moved Gilder to 11-under 133, one shot better than Bobby Wadkins and three in front of John Mahaffey and Dick Mast.

"I figured something out on the practice tee and the momentum just built as the round went along," Gilder said. "I knocked the flag down on two of the last three holes. Everything fell into place."

That included a 25-foot putt on the par-5 18th hole that followed a pair of 3-woods and found the bottom of the cup, giving Gilder the lead.

"The putt at the last hole was one of those that felt good and looked good," he said. "It was just inside left."

Gilder's closing rush began at the par-4 12th, where his 9-iron approach stopped three feet from the cup. He parred the par-3 13th and 15th holes around a 10-foot birdie at the par-4 14th.

On the par-4 16th, Gilder again used a 9-iron approach and hit the flagstick before tapping in another three-footer. His pitching wedge on 17 also hit the stick and left him with an 18-inch birdie.

"Bob's a good player," said Wadkins, who fired a 65. "He can get on a hot stretch. He's been a good player for a long time."

After winning twice in his rookie season on the Senior Tour, Gilder has been unable to break through this year. However, he has been showing signs of late, closing with a 63-64 and finishing fifth at the Canada Senior Open.

"I'm a little disappointed I'm not winning, but then again, I haven't played well enough to win," Gilder said. "My game just hasn't come together yet. Maybe this is the week."

Wadkins also played bogey-free, opening and closing with consecutive birdies. Another second-year player, he won the 2001 Long Island Lightpath Classic.

"Ever since I've won, I've played extremely well," he said. "I had three seconds this year and have just gotten beat by a better round."

Mahaffey also had a bogey-free 65 with a finish similar to Gilder's. He was 1-under through 10 holes before holing birdies at six of the last eight holes.

"I played pretty well," said Mahaffey, whose lone Senior Tour victory came at the 1999 Southwestern Bell Dominion. "I didn't make many mistakes. We're getting used to the course a little better."

Mast shot a 64 that included 10 birdies, including six in a row from Nos. 8-13.

"It's very encouraging," he said. "I've been inconsistent this year. (I've had) lots of bogeys and I still had two bogeys today. I've been hitting lots of quality shots but not repeating them enough."

First-round leader Ted Goin was one of the few players over par, carding a 73 that left him six shots off the pace.

Defending champion Dana Quigley used a 7-iron from 163 yards for a hole-in-one on the 13th. A 69 left him at 3-over 147 and out of contention.

Instead, the field will be trying to track down Gilder, who has positioned himself for the $217,500 first prize.

"It's hard to do," he said. "I try to take it one shot at a time and and not get ahead of myself. Who knows what's going to happen tomorrow?"