Bernhard Langer took a three-shot lead in the Senior British Open after shooting a 2-under 69 in the third round at Carnoustie on Saturday.
The German has yet to win on the U.S. Champions Tour but is in position to change that after outplaying his nearest rival, Corey Pavin.
The pair set out as co-leaders at 4 under, but three bogeys dropped the American Ryder Cup team captain to a 1-over 72.
Despite his lead, Langer was wary of Carnoustie's fearsome reputation.
"I am aware that this golf course is one of the toughest links you will ever play," he said. "And I am aware that a three-shot lead is nothing if very little around here. I am going to have to play very solidly again in the final round if I am going to lift the trophy."
Langer's lead would have been even greater but he drove into a bunker on the final hole and was forced to lay up short of the infamous Barry Burn with his recovery shot.
He then hit a wedge to five feet but missed the putt to save his par and had to settle for the three-shot lead with a 6-under 207.
After his round, Langer said he wished he had used a different club off the 18th tee to take the bunker out of play.
"I hit a 3-wood," he said. "But my caddy and I also discussed hitting one less — a hybrid. I should have listened but I am a stubborn German."
Despite falling out of the lead, Pavin was upbeat about his performance.
"I played fairly well, and a lot of putts just missed. Sometimes you have days like that," Pavin said. "Bernhard played really solidly and I can't really expect him to come back and then again I can't be aggressive on Carnoustie and try to kill it, because it will kill you if you try to do that."
A group of six players go into the final round at 2 under, one shot behind Pavin and four off the lead.
Five of them are Americans, reflecting three days of domination at the top of the leaderboard.
Funk climbed more than 15 places after a bogey-free 4-under 67, the lowest round of the day.