Bill Haas had another bogey-free round at Riviera Country Club for a 7-under 64 -- the best round on Saturday by three shots -- and a three-stroke lead going into the final round of the Northern Trust Open in Los Angeles.

On a warm afternoon off Sunset Boulevard that made the greens even faster, Haas turned in a remarkable score. The key was a seven-hole stretch in the middle of his round that he played in 6 under par, including a 60-foot pitch that dropped for eagle on the scary par-4 10th hole.

He was at 12-under 201 and will try to become only the eighth back-to-back winner in the 76-year history of this PGA Tour event. All he cares about Sunday is winning.

"It's very difficult in this game to just pull away from the rest of the field," Haas said. "You've only seen a few guys ever really do that, and those are guys like Jack Nicklaus, Tiger Woods, Phil Mickelson. So I think I've just got to stay in the moment, don't let my emotions get the best of me."

A year ago, Haas was two shots behind going into the final round and wound up winning in a playoff over Mickelson and Keegan Bradley. This time, he has a comfortable margin over U.S. Open champion Webb Simpson and former Masters champion Charl Schwartzel, who each thought they did well for a 68.

John Merrick bogeyed the 18th hole for a 70 and joined Simpson and Schwartzel at 204.

Mickelson was hopeful of making a move and instead went the other direction. He missed three par putts of about 6 feet on the front nine and had a 72, putting him nine shots behind Haas.

The round started with 20 players separated by five strokes. Thanks to Haas and his flawless play, only eight players were within five shots of the lead.

Champions Tour: Bernhard Langer shot a 2-under 70 to take a three-stroke lead after the second round of the ACE Group Classic in Naples, Fla. He had 16 pars and two birdies in windy conditions for a 12-under 132 total. Chien Soon Lu (68) and Tom Pernice Jr. (69), who was runner-up last week in Boca Raton, Fla., were tied for second.

LPGA Tour: Jiyai Shin and 15-year-old amateur Lydia Ko shot 3-under 70s to surge six strokes clear of the field heading into the final round of the Women's Australian Open at Royal Canberra. Both were at 17-under 202.

Beatriz Recari (71) was third. American Stacy Lewis, the 2012 LPGA Player of the Year, was 10 shots off the lead after a 69.