Tom Watson scrambled magnificently to keep the lead in the third round of the British Open on Saturday as, at 59, he closed in on becoming the oldest ever winner of a major.

The American, a five-times former winner of the event, was bunkered at both the third and fifth holes, but on both occasions he walked away with a par as he remained at five under for the tournament.

He was not so fortunate after another visit to the sand at the par-three sixth, missing a 10-footer for par.

The man he shared the halfway lead with, compatriot Steve Marino, had a dreadful start, running up three bogeys from the second hole followed by a double bogey to slip off the leaderboard.

The unlikely pairing of 59-year-old links master Watson and 29-year-old links rookie Marino took everyone by surprise at Turnberry.

But the Americans were facing a pressure-filled day as 19 other players were also under par and gunning to remove them from atop the leaderboard.

Two times former US Open winner Retief Goosen closed to within one-stroke of the lead with a birdie at the second but he found heavy rough on the par-five seventh and walked off with a double bogey seven.

Top British and European challenger Ross Fisher also made an early move with a birdie at the 3rd but promptly dropped one at the fifth to stay at three under for the tournament, one behind Watson.

Level with him were Japanese surprise Kenichi Kuboya through seven holes and 49-year-old American former winner Marc Calcavecchia who was on the seventh.

Thirty-year-old Open debutant Bryce Molder, meanwhile posted the early target in the clubhouse with a three under 67 which left him even par for the tournament on 210.

Thailand's Thongchai Jaidee joined him there when he carded a one-under 69 to keep alive hopes of a first Asian win in a major.

Earlier Ireland's Padraig Harrington had seen his hopes of an historic hat-trick of Open titles bite the dust.

Having only just squeezed into the weekend's action at three over par, eight shots behind Watson and Marino, Harrington needed a storming round on Saturday to get back in contention.

A cold putter put paid to that as he staggered in with a six over 76 ending any realistic hope of getting back into contention for Sunday.

Harrington won the Open at Carnoustie and Birkdale and a third triumph here on Sunday would have made him the first man since Australian Peter Thomson in 1956 to lift three in a row.

"Obviously I needed things to go well for me and hole a few putts today but it just didn't happen," he said.

Also out of the picture was another Irish hope, 20-year-old Rory McIlroy, who went out in 40 despite an eagle at the seventh. Two double bogeys and three bogeys did the damage.

He did manage a strong finish with birdies at the last three holes but his 74 left him seven over for the tournament and effectively out of the running.

"Not really," he replied when asked if he could get back in contention on Sunday. "I struggled all week to be honest and I struggled last week."