The unknown 25-year-old fired a five under par 67 in the third round at Santa Ponsa to carry a one-stroke advantage into the final 18 holes tomorrow.
Walker, who cut Alcott's lead of five shots to a one-stroke advantage after 12 holes, finished with 69 for 276.
From there, Garcia hit a beautiful flop shot that landed 4 feet from the pin and made the putt for birdie to take a one-stroke advantage.
That one-stroke advantage held up for Singh, even though he missed a 6-foot attempt for another birdie at No. 17.
But Singh responded with consecutive birdies at Nos. 9, 10 and 11, turning a one-stroke advantage into a commanding four-stroke cushion.
Four consecutive pars to finish the round allowed Moody to preserve the one-stroke advantage and the championship.
Heading into the final round, he owned an one-stroke advantage over Andy North, who shot 65 in the second round and 70 in the third.
Bradley made his birdie put, while Dufner missed his birdie, allowing Bradley to take a one-stroke advantage to the 17th.
He shot a 71 and will take a 212 total and a one-stroke advantage into today's final round.
Storming into the lead at the Buick Open today with a seven-under-par 65, Furyk held a one-stroke advantage heading into Sunday's final round.