Tony Finau completed a magnificent 64 - the third of the day - to claim the clubhouse lead as round three of the Masters neared its conclusion.
When Finau parred the 18th to end his penultimate round at 11 under for the tournament, he held a one-shot lead over Xander Schauffele, who had played 13 holes.
Webb Simpson, Tiger Woods and Francesco Molinari were a stroke further back, but the latter duo and several others still had time to improve their positions as they reached Augusta's closing holes.
Finau, who dislocated his ankle in last year's par-three contest, had begun the day four behind the leaders, but was out in front before he made the turn following a sensational start to his round.
Birdies at each of the first three holes were augmented by another at the sixth, before he came agonisingly close to an albatross at the par-five eighth, a stunning second shot setting up a tap-in eagle.
A 10-foot birdie chance went begging on the next hole, meaning Finau was unable to become the first man in history to shoot 29 on Augusta's front nine.
However, he made fours on each of the par-fives on the back nine, before parring the final three holes to miss out on a share of the course record by one.
Patrick Cantlay and Simpson had each shot 64 earlier in the day to reach six and nine under respectively.
"The wind was down and it was just humid, so the greens were receptive," said 2012 U.S. Open champion Simpson after his round.
"With this sun coming out, a little breeze, it might not be as receptive coming in [for the later starters]. I will have a chance no matter what they do.
"I know we have storms coming in tomorrow [Sunday], so who knows what the scores will be like."
Due to the threat of inclement weather, Sunday's final round will start much earlier than usual, with players going out off the first and 10th tees and the leaders scheduled to start at 9:20am local time.