Tiger Woods mounted a brief charge in the early stages of the Masters third round on Saturday, but quickly fell back again.
Starting the day eight strokes behind American co-leaders Freddie Couples and Jason Dufner, Woods was looking for a quick rebound after his swing nightmare down the back nine on Friday.
He got just that with birdies at the third and fourth to get to one over, but then he dropped one at the par-three sixth and a wild drive on the ninth saw him collect another bogey to reach the turn where he started the day at three over.
Couples and Dufner took a one-stroke lead into the third round but a packed leaderboard and the second-biggest weekend field in the tournament's history were primed to challenge them.
Couples is seeking his second Masters title and second Major at the age of 52, 20 years after his last and only triumph at Augusta National.
He is the oldest player to lead the Masters at the halfway stage and, should he win on Sunday, he will become the oldest man ever, by four years, to win a major title.
The 36-year-old Dufner is a journeyman who has yet to win a tour event but who came agonisingly close at last year's USPGA when he led by four shots with four to play but lost to Keegan Bradley in a play-off.
Fan favourite Couples said that he is ruling nothing out.
"Can I win?" he said. "I believe I can, yes. I feel very young when I get here."
He knows though that the traditional third round "Moving Day" is likely to be fast and furious.
Five players are one shot behind the co-leaders at four under, headed by tournament favorite 22-year-old Rory McIlroy of Northern Ireland.
They also include World No. 3 Lee Westwood of England, Sergio Garcia of Spain, British Open champion Louis Oosthuizen of South Africa and Bubba Watson of the United States.
Three others -- Matt Kuchar of the United States, Spanish veteran Miguel Angel Jimenez and 1999 British Open champion Paul Lawrie from Scotland -- are a further stroke back.
In all, 30 players are within five strokes of the lead in the 63-strong field that made the cut, matching 1992 as the biggest in Masters history since the 64 who made it though to the weekend in 1966.
McIlroy, who squandered a four-shot lead in final round at last year's Masters, has gradually worked his way up the leaderboard after a double bogey start on Thursday and was installed as a 3/1 favorite after his 68 on Friday.
The reigning US Open champion feels confident he has banished the Augusta National demons that consumed him here 12 months ago.
"Every time you come back here, I think you feel a little more comfortable," he said.
Westwood and Garcia will be seeking to win their first Majors after several close calls for both of them over the years while Oosthuizen will be out to make it back-to-back wins for South Africans after Charl Schwartzel's thrilling victory last year.
Three-time former winner Phil Mickelson was handily placed at three shots off the lead after nearly derailing in the first round.
Among the early starters on Saturday under the best playing conditions of the week so far, South Korea's Bae Sang-Moon and Webb Simpson of the United States both picked up two shots on the front nine to get to level par.
World No.1, Luke Donald, who started the day at a disappointing four over, eagled the third and birdied the eighth. But bogeys at five, 10 and a double-bogey seven at the 13th appeared to rule him out of contention.
