Steve Stricker recorded a sensational course-record round of 64 to put himself firmly in the hunt for the Open title at Carnoustie on the third day.
Stricker enjoyed a blemish-free round to join the leading pack
The 40-year-old American did not drop a shot and struck seven birdies to move to six under par for the tournament.
"That's the best round of my career by far and it is special just to have a shot at the title," he told BBC Sport.
His round eclipsed that of compatriot Chris DiMarco, who also stormed up the leaderboard with a five-under-par 66.
But Stricker was refusing to get carried away, with 18 holes of golf left to play on Sunday.
"This whole day has been pretty magical and to go round without a blemish is all the more satisfying," he said.
I think the key to the course at the moment is to not feel like you have to go big with every shot
"But I've got to keep my head down, keep working and hopefully then the good things will come.
"I haven't even thought about what it would mean to mean to win here yet. There are 18 holes to go and I'm just glad to be in the running."
DiMarco, meanwhile, believes he is beginning to conquer the Carnoustie course after sinking seven birdies and two bogeys to move to three under.
"I found something on the range yesterday," he said. "My drives clicked and my iron play has been really good. I'm hitting right at the hole and it's coming together.
"I feel I've got the strategy down. I just hope I can keep it together."
DiMarco made the most of the favourable conditions to shoot a 66
He added: "I think the key to the course at the moment is to not feel like you have to go big with every shot. You use the woods, you use the irons and then you can make big putts."
DiMarco's round was the best in the clubhouse by mid-afternoon, having made the most of friendly conditions for low scoring.
And the 39-year-old revealed he has been playing through the pain barrier "for months".
"I've never had to play through injury before, and it's no fun I tell you," he said.
"My shoulder is hurting and it causes me trouble from time to time, but 66s help ease the pain and I'm sure it won't be a problem tomorrow."
World number four Ernie Els carded a triple-bogey eight after firing out of bounds at the 6th but still managed to carve out an impressive 68 with the help of five birdies on his remaining holes.
"If I could have that one tee shot over I could have been a lot closer," said the South African.
"There were really a lot of scoring opportunities and I had a lot of fun except for that one hole. You know, on a birdie-able par five, downwind, that is really giving three of four strokes back to the field.
"I've got to keep this momentum going and keep the eights off my card. Sergio Garcia is going for his first major and there is a lot of things for him to think about tonight. It is not easy.
"I wish him the best but I'd like to give him a good go tomorrow."
Jim Furyk is a shot behind Els after a mixed level-par 71.
The 2003 US Open winner had an entertaining back nine, carding four birdies and two bogeys before dropping a shot at the last for the third straight day.