Tom Watson nearly shot his age on Thursday as he opened with a 4-under 66 at the U.S. Senior Open Championship and was one stroke clear of six players.
Watson is a three-time runner-up in this championship, including a playoff loss to Don Pooley at the 2002 Senior Open. Watson has won six majors on the Champions Tour with his last coming at the 2011 Senior PGA Championship.
"Man, did I want to make that putt. I was grinding on that putt more than any putt in a long time," said Watson of his birdie try on the ninth, his final hole. "Shoot my age in a U.S. Open Championship, that would have been pretty special."
A pair of former second-place finishers, Mark O'Meara and Gene Sauers, are part of a large group at minus-1. O'Meara finished second to Olin Browne in 2011, while Sauers fell in a playoff to Montgomerie last year.
Watson, 1982 U.S. Open champion, poured in a long birdie effort on the par-4 11th to get on the board. He followed that with a trio of pars. Watson moved to 2-under with a birdie at the long par-5 15th.
The 65-year-old gave both those strokes back as he faltered to a double-bogey at the 16th. He fought back after three pars in a row around the turn.
Watson ran home another long birdie try from about 50 feet out on No. 2 to get back into red figures. At the par-5 fourth, he collected his fourth birdie of the day.
The eight-time major champion on the PGA Tour posted back-to-back birdies at six and seven to move into the lead at minus-4. Watson parred the final two holes to end there.
"The U.S. Open, hit the ball on the fairway. If you don't hit the ball on the fairway, you are penalized. That's the way it should be, especially around the greens," Watson said. "If you miss the ball around the greens, it is very tough to judge the shot. The grass is really, really gnarly, thick, lush, grows different directions, and it's just a guess."
Janzen, who played one group ahead of Watson, got off to a quick start with birdies at 10 and 11. He posted his third birdie at the 15th and followed with his second run of three pars in a row.
Around the turn, Janzen moved to 4-under with a birdie at No. 1. After another trio of pars, he tripped to his first bogey at the fifth. Janzen birdied the sixth, but gave that right back as he dropped another shot at the seventh. He parred the last two holes to end one behind Watson.
Austin had bookend birdies at one and nine on the front nine. In between, he carded seven pars in a row. After faltering to a bogey at 13, Austin birdied the next two holes and closed with three pars.
Hart birdied one and two and followed with four consecutive pars. He notched another birdie at seven, then closed his round with 11 straight pars.
Carter also had a bogey-free round with birdies at one, nine and 12. Horgan opened with six straight pars, then birdied four of five holes from the seventh. He wrapped bogeys at 14 and 16 around a birdie at 15.
Allen played in front of Janzen. Allen had three birdies and two bogeys on his first nine holes. He moved to 4-under with birdies at one, two and six. Allen faltered to a double-bogey at the eighth, but got one back with a birdie at the ninth, his last.
NOTES: This was the first time Watson had sole possession of the first-round lead since the 2010 season ... Hale Irwin, 70, shot his age for the 10th time on the Champions Tour ... Marco Dawson's streak of holes without a 3-putt ended at 140 when he 3-putted the sixth ... Sutherland is a member at Del Paso ... Paul Wesselingh had the only eagle of the day and it came at the 15th.