Phil Mickelson will take a one-shot lead into the final round at Augusta.
US unless stated
-4 Phil Mickelson
-3 Chad Campbell, Fred Couples
-2 Stephen Ames (Can), Tiger Woods, Tim Clark (SA), Darren Clarke (NIre), Vijay Singh (Fij), Rocco Mediate
-1 Miguel Angel Jimenez (Spa), Retief Goosen (SA)
Even Jim Furyk, Stewart Cink, Billy Mayfair, Ernie Els (SA)
The 35-year-old American, who won here in 2004, bogeyed the last to fall back to four under but then watched as his closest rivals also faltered.
Playing with Mickelson in the last pairing will be the 46-year-old Fred Couples - the winner has come from the final group every year since 1990.
It is 20 years ago since another 46-year-old, Jack Nicklaus, stunned the field to win the Masters.
Either man would be a popular and worthy winner.
Couples, the 1992 Masters champion, has never missed a cut in 22 trips to Augusta, while Mickelson, who won his second major at the USPGA last season, has had five top-three finishes in his 13 previous Masters appearances.
But with 15 players, including the rest of golf's "big five", within four shots of the lead it will not be easy.
Alongside Couples on three under is overnight leader Chad Campbell, who posted a three over 75 to slide from his 36-hole score of six under.
On two under are Stephen Ames of Canada, South Africa's Tim Clark, Darren Clarke of Northern Ireland, Fijian Vijay Singh, who led after the first round, and American pair Rocco Mediate and Tiger Woods.
That last name will worry Mickelson most, as the world number one is the only player here with an even better Masters record than him - four wins in 11 visits.
The 37-year-old Clarke would be forgiven for wondering how he is not playing in the same group as Mickelson for the second straight round, but with his new relaxed approach to golf he probably is not too upset.
The Ulsterman was in excellent shape after a superb eagle at the 13th got him to four under and a tie for second. But he then visited the water twice at the 15th to run up a triple-bogey eight.
But he then showed great character by bouncing back with a birdie at 16 to return to two under for the tournament.
"I don't make two after an eight unless my head's OK," Clarke said before preparing himself for the final round.
"You couldn't have told the difference in me if I'd made four or eight - and that can only be a good thing.
"So I made a triple bogey. Big deal. Everybody's making mistakes. These things happen out there."
His near namesake from South Africa would also be excused for harbouring regrets. Clark was on fire when the light failed on Saturday, but struggled on the inward nine of his third round on Sunday, dropping four shots in five holes to fall out of the lead.
A shot further behind the six at two under, are world number three Retief Goosen of South Africa, and Spain's Miguel Angel Jimenez, who completed a superb three-under 69 on Sunday morning to rocket up the leaderboard.
And the four players on even par - Jim Furyk, Stewart Cink, Billy Mayfair and Ernie Els - will also still feel they have an outside chance of success, particularly world number five Els, who has been runner-up at Augusta twice.
The fourth round, delayed by the long interruption on Saturday because of thunderstorms, starts at 1110 local time (1610 BST), with the leaders starting nearly four hours later.
When asked about the significance of playing in the final group at Augusta on Sunday, Mickelson said: "I didn't give it much credence yesterday, but now I am leading I like that stat.
"Yes there's pressure, but it's what you dream about as a kid and what you work for as a pro."