Americans Phil Mickelson and John Daly saw their Open challenge rise and fade in tricky third rounds at St Andrews.
Mickelson collected four birdies to move to seven under before two bogeys and a double bogey saw him card 72 and slip back to three under.
Daly, Open champion at St Andrews 10 years ago, also moved to seven under after birdies at the first three holes.
Three bogeys after the turn dented his hopes before a birdie at the last left him in the hunt at six under.
World number three Ernie Els failed to spark, as a third round 75 saw him fall well off the pace.
Els, who finished on level par, got off to an unhappy start with three putts at the first for a bogey and he never got his round back on an even keel.
Another bogey at the fourth damaged his scorecard, and even birdies at the seventh and ninth could not get his
Three bogeys on the back nine - at the 10th, 11th and 17th - stopped his attempted comeback in its tracks.
Earlier American legend Tom Watson had an extraordinary run of scoring in a round of 70 that lifted him to one under.
The 55-year-old had three outward birdies, but bogeys at the seventh, 11th and 12th were followed by a hat-trick of birdies from the 14th.
"I didn't like this course at first but it has grown on me," said Watson, who then birdied the last.
"I didn't like the humps and bumps, the blind shots and how firm the golf course plays."
Watson, who won the last of his eight majors at the 1983 Open, has only missed one Open since his victory on his debut in 1975.