Martin Kaymer says he will not change his game plan to defend a five-shot lead he believes can "vanish" in round four of the US Open.
The German, 29, was two over on round three, where only Erik Compton and Rickie Fowler - who share second - were under par at a testing Pinehurst.
"The biggest challenge is not to get defensive," said Kaymer. "Your game plan changes and you don't swing free."
Kaymer, chasing a second major, tees off with Fowler at 20:35 BST on Sunday.
Having claimed the Players Championship in May, success in North Carolina would reaffirm Kaymer's return to form after struggling with swing changes since his maiden major victory at the US PGA Championship in 2010.
His first bogey in 30 holes arrived on the second in round three and a volatile round which included an eagle, was concluded with a birdie on the 18th.
"I kept it together well. It's nice to have a lead, but it can vanish," he added.
"If you have a lead of four shots, five shots, six shots... at the end of the day, if you play a golf course like this it can be gone very quickly."
Kaymer's fear of a testing time on Sunday was lived out by many of his rivals in round three, as Pinehurst - a par 70 - averaged 73.8 strokes.
That mark was the highest of the week so far, but the rapid greens could not hamper Fowler and Compton from maintaining a challenge on three under.
Compton has survived the cut for a first time in a major, but after enduring two heart transplants during his 34 years, he feels at ease with the scrutiny major competition provides.
Asked what winning the US Open on Father's Day would mean, he said: "I might just sail off and never play golf again.
"I felt so comfortable out there, maybe because I've been in so many pressure situations in my life and to be out here playing golf is a pleasure."
Miami-born Compton has never won on the PGA Tour but like Fowler - a Tour winner at the Wells Fargo Championship in 2012 - shot 67 on round three.
Fowler, 25, said he was carrying out his objective of contending for majors this year.
"I can put myself in contention with the rest of the group, and see what Martin does," he said of Sunday's final round.
"If he goes out and posts double digits (under par), it's going to be impossible for us to catch him. It's like a second tournament going on."
England's Justin Rose is the most prominent British challenger but on one over par, conceded he thinks he is "four or five shots too far back."