Turnberry, Scotland ? Tom Watson’s bid to win his first major as a senior was upstaged by his playing partner Friday — and it wasn’t Jack Nicklaus.

The Senior British Open was billed as a rematch of the 1977 British Open, when Watson edged Nicklaus by one stroke at the same Turnberry links. Only someone forgot to tell Carl Mason.

The unheralded Englishman shot a bogey-free 6-under-par 64 to take a one stroke lead into today’s third round at 9-under 131.

Watson added a 67 to his first-round 66 and is tied for third behind D.A. Weibring, who had a 63 for 132. Tom Kite also shot a 67 and is tied with Watson and another American, Bruce Summerhays (65), at 133.

“I putted very well today, but my golf swing was held together by bailing wire and duct tape today,” said Watson, a five-time British Open winner.

“I played a very scratchy round, and I watched Carl Mason play a very, very good round of golf. He was very precise in what he was doing, and I need to pick up on that and do the same.”

Arnold Palmer birdied three holes in a row from the second. But 10 bogeys in a round of 77 and a halfway total of 13-over 153 means he missed the cut by a long way.

A two-time winner on the regular European tour after 20 years without a victory, Mason was supposed to be the supporting cast to Watson and Nicklaus. The trio was followed by the only big gallery on the course.

“It feels great, absolutely great,” Mason said after walking off with the lead. “I felt a little bit nervous on the first tee. That’s pretty normal with the company I was keeping.”

Tom Watson, left, and Jack Nicklaus walk off the course. The two played the second round of the Senior British Open Championship Friday in Turnberry, Scotland.

Watson, starting at 4 under, lost a stroke with a bogey at No. 5. But he followed with an eagle-3 at No. 7 and birdied two holes on the back nine. Mason closed in 33 after totaling two birdies. Nicklaus, who was at par at the start of the round, made up for a double bogey-5 at the fifth with five birdies.

“I’m in good shape, the best shape I’ve been in a tournament for a long time,” said Nicklaus, who has been plagued by back and neck injuries. “It’s the first time this year I’ve felt like I’m playing golf. … I’ve participated, but I haven’t really played golf.”

The Golden Bear admired the play of Mason and Kansas Citian Watson.

“Mason holed a ton of putts. Tom holed a flood of putts today,” he said.

“But that’s what you’ve got to do. It’s the first time I’ve seen Carl play, and he played very nicely.”

Weibring, a five-time winner on the PGA Tour who is in his rookie season as a senior, charged into contention by carding eight birdies. He marred his round by driving into the rough at the last hole.

“I didn’t like the bogey at the last, but this was a good opportunity to score well,” he said.

“I’ve shot a bunch of 64s on par 72s and 71s, but it might be my lowest number, although not the lowest under par. Sixty-two would have sounded good, though.”

It sounded good to Jim Colbert, who fired a 62 to tie the course record set by Harold Henning in the 1990 championship. He made an eagle and seven birdies with just one bogey, at the sixth.