Ernie Els stayed on course for his fifth title of the year on Saturday, firing a four-under-par 67 in the Scottish Open third round to forge five clear of the field.
The British Open champion, following opening scores of 64 and 67, mixed five birdies with a bogey in calm but overcast conditions at par-71 Loch Lomond, finishing at 15-under 198.
Northern Ireland's Darren Clarke fired a six-birdie 64 to climb to second place at 10 under, level with Britain's Phillip Price, Els's playing partner, who returned a 68.
Best round of the day, however, came from 1992 champion Peter O'Malley of Australia, whose flawless nine-under-par 62 lifted him into fourth spot at eight-under 205.
But O'Malley's effort, which equalled his career low set in the 1992 Scottish Open at Gleneagles, will not officially match the course record fired by Retief Goosen in 1997 as preferred lies were in operation for the second successive day.
South African Els, four strokes ahead overnight, picked up shots at the third and ninth to reach the turn in two-under 34, at that point still four clear of the chasing pack.
Further birdies followed at the 345-yard 14th, where he drove the green, and at 15, but the world number two then dropped his only shot of the day at the par-four 16th, where he missed the green with his approach.
However, he bounced back with a fifth birdie at the last, holing out from six feet, to stay on track for his second Scottish Open title, his first coming at the same venue in 2000.
"I want to go out tomorrow and play like I've been playing," said Els. "I couldn't hit it better off the tee, really.
QUITE TOUGH
"I saw a few flags out there for the final round and they look quite tough," he added. "So it's going to be difficult to shoot very low, which will make it a little bit easier for me."
Els, who will launch his British Open defence at Royal St George's next Thursday, agreed a second Scottish Open title was in his own hands.
"Yes, definitely," he said. "With a five-shot lead, the way I've been playing, I've got to go out there and do my business, and somebody's got to shoot very low, probably, to beat me."
Clarke, who played with Els for the first two days, was delighted with his own ball-striking.
"It was very good today," he said. "I drove the ball well, hit my irons an awful lot better and hit a lot of good putts.
"But 64 is probably the worst score I could have shot out there. I missed from about five feet on the first, from four feet on 13 and a few others here and there -- otherwise it could have been a very, very good score."
Asked what he needed to give himself a chance of overhauling playing partner Els in the final round, Clarke replied: "Probably better tomorrow, I'd imagine.
"I'll just have to play the same and putt a little bit better. But it's possible."