KETTERING, Ohio - Craig Stadler thought a 68 would be a great way to start the U.S. Senior Open.

But once he put the finishing touches on a record-tying 7-under-par 64, Stadler had to re-evaluate his thinking.

"I came out this morning and looked at the board and there were a couple of 3-unders, a couple of 2-unders, and I thought it was pretty good scoring," Stadler said Thursday. "Obviously, it was much better this afternoon."

Stadler's score matched the Senior Open first-round record and gave him the top spot on a leaderboard that included Greg Norman and Tom Watson. Tom Purtzer is a shot back, with seven others within three strokes.

"Starting out like today is wonderful," Stadler said. "I expected to have somewhat of a decent week this week. I don't think anybody expects to shoot 63 or 64 every day. It's certainly nice when it happens."

Stadler birdied his first two holes at NCR Country Club and never let up, finishing with six birdies, an eagle and one bogey.

Butler's John Aubrey Sr. fired a 2-over 73 in the first round Thursday, putting him nine strokes behind Stadler.

Last year, Aubrey made the cut at the Senior U.S. Open held in St. Louis.

He has some work to do to make the cut this year and 61 golfers appear above him on the leaderboard.

Purtzer, playing two groups behind Stadler, opened eagle-birdie in a 65.

"When you get off to a start like that, it kind of helps get your momentum going, to get some positive thoughts flowing," Purtzer said. "That definitely helped."

Loren Roberts, playing in only his second seniors event, was alone in third at 66.

Bruce Fleischer shot a 67, followed by five players at 68 including Norman and Watson.

Thirty players broke par in the opening round, matching the tournament record set in 2000 at Saucon Valley.

Stadler's round tied the mark set by Fleischer in 2000 and matched in 2002 at Caves Valley by R.W. Eaks.

Coming off a fourth-place finish last week at the Senior British Open, Stadler hit 16 of 18 greens in regulation and needed 30 putts. He played the three par-5s in 4 under, eagling the 549-yard 6th. After his drive, he hit a 3-wood pin high and 18 feet away, then rolled in the putt.

On the next hole, a 425-yard par-4, he hit an 8-iron to 6 feet for the birdie that gave him the lead.

"You hit anything marginally good with the irons, you're going to have a fairly makable birdie putt," Stadler said.

Purtzer, like Stadler, also started on the 10th hole but began with an eagle, hitting a 3-wood to 20 feet and making the putt. His pitching wedge second shot ended up 6 feet away on the next hole and he made that to get to 3 under through two holes.

Purtzer posted his second eagle of the day on No. 6, making a 12-foot putt, before three-putting the next hole to fall a shot off Stadler's pace.

Norman, also making his second seniors start, didn't have a bogey in his 68.

"I didn't make any mistakes today, kept the ball in play, hit a lot of greens and probably the only flaw on my whole day was I didn't make the putts that I thought I would," said Norman, who needed 33 putts.

Watson, who won the Senior British Open, another major, in a playoff last week, averaged 290 yards on his two measured drives. He was pleased with his consistency.

"Sixty-eight is a pretty good start," Watson said. "I'm getting more familiar with the golf course day to day."

Norman and Watson were joined at 68 by Dick Mast, Wayne Levi and Bruce Summerhays. Raymond Floyd, who won the PGA Championship at NCR Country Club in 1969, was at 69.

Curtis Strange, the 1988-89 U.S. Open winner, shot a 71 - including a hole-in-one on the par-3 13th.

Hale Irwin, who won Senior Opens in 1998 and 2000, shot a 71. Defending champion Peter Jacobsen shot a 72, playing the final three holes 3 over.