Adam Scott is still within striking distance at the Northern Trust Open, but the Australian will have to produce a brilliant final round to overhaul American Bill Haas.
Scott could only manage a 70 during his third round on Sunday and will head into his final 18 holes on Monday some seven shots behind Haas at five-under for the tournament.
Haas was flawless for the second consecutive day, managing five birdies and an eagle on the difficult par four 10th as he improved eight places from his overnight position to move to 12-under par overall.
Haas will now try to become the eighth back-to-back winner in the 76-year history of the tournament at the Riviera Country Club in California but is by no means assured of victory with a group of three players comprising of Webb Simpson, Charl Schwartzel and John Merrick tied for second and within striking distance at nine-under for the tournament.
Reigning US Open winner Simpson and former Masters champion Schwartzel each shot three-under rounds of 68 while Merrick finished the day with a one-under par 70.
Joint overnight leader Fredrik Jacobson is a shot further back on eight-under after a disappointing round of 72 with Luke Donald joining him in a tie for fifth after he carded 70 for the day.
South Korea's Sang-Moon Bae, who went into the third round with a share of the lead with Jacobson, found the pressure too much to handle as he hit five bogeys and a double bogey to finish with a five-over par round of 76 to drop to joint 13th on the leaderboard at four-under for the tournament.
American pair Josh Teater and Charlie Beljan are in a tie for seventh at seven-under, Hunter Mahan and Spaniard Sergio Garcia round out the top 10 at six-under par, while Scott is a further shot adrift at minus five.
It was a mixed day for the remainder of the Australians that made the halfway cut, with Greg Chalmers, Stuart Appleby and Marc Leishman all picking up their fair share of birdies and bogeys.
Chalmers carded a 73 and shares 22nd place at two under, Leishman managed a 68 to move up to minus one, while Appleby shot a 71 and is another shot back.