Carl Mason is the surprise leader at Turnberry

That gave him a third round 65, the same as playing partner D A Weibring, who followed up his second round 63 to keep the pressure on Mason.

The Englishman goes into Sunday's final round on 14 under par, with Weibring a shot back on 13 under par.

Tom Watson and Tom Kite both scored 66 to stay in contention at 11 under par alongside Bruce Summerhays ahead of what promises to be a thrilling final round.

Mason's round featured six birdies and just one dropped shot at the unlucky 13th.

"I have to admit I felt a bit flat during the first few holes, which I don't suppose was all that surprising considering I played the first two rounds with Jack Nicklaus and Tom Watson," admitted Mason afterwards.

"But the birdies on five and seven settled me down and I was fine after that."

It's been a great experience and I would like to think I can keep things going Carl Mason

"Tomorrow I will be flying the flag for the European Seniors Tour. It looks like it's going to me against all the Americans, which is going to be a lot of fun."

Mason's playing partner Weibring also carded six birdies, dropping a solitary shot at the sixth.

Watson had just one blemish on his 66 when he also bogeyed 13 after pitching over the green.

Kite recovered from a disastrous double bogey seven at the 17th, where he drove onto a bank in the left rough, to birdie the last, his sixth birdie of the day.

Nicklaus also took advantage of near windless, sunny conditions and picked up four shots to move to eight under after 13, only to spoil his round with bogeys at 15 and 18.

He wound up with a 67 - his second in a row - and a six-under total of 204 in a tie for ninth place.

Defending champion Noboru Sugai's third round was littered with bogeys and despite an eagle three at 17, he finished with a two-over-par 72 to leave him two over for the tournament.