Bill Haas leaves field in his Wake with a 64

Saturday was moving day at the Northern Trust Open and no player was more moved than Bill Haas.

He was also inspired and motivated even if he was relatively unchallenged.

The tournament’s defending champion shot up the leaderboard with a brilliantly managed, bogey-free, seven-under-par 64.

Haas’ round matched the brilliant blue sky over Riviera Country Club and was three shots better than anyone else Saturday.

Haas started the day tied for ninth, four shots back, and finished looking back at the field. He stands at 12-under 201 through 54 holes, and the bad news for the field is he’s getting better as the tournament moves along. Haas’ 64 followed rounds of 70 and 67.

Haas has a three-shot cushion over three players at nine-under 204 — Webb Simpson, Charl Schwartzel and John Merrick.

Luke Donald and Fredrik Jacobson are four shots back at 205. Donald shot a 70 Saturday while Jacobson shot a 72.

Phil Mickelson started play five shots back of co-leaders Sang-Moon Bae and Jacobson but sputtered like a prop plane on his way to a 72. He dropped to three under and nine behind Haas.

Mickelson, after a bogey on No. 18, was still the star of the rail outside the hilltop clubhouse, signing autographs as Haas passed him on his way to the scorer’s room. Unless Mickelson has another 60 in his bag left over from the Phoenix Open, it’s hard to see him making a Sunday run.

Haas played in overdrive on a day everyone else seemed stuck in neutral.

His 64 was being universally heralded on a day when warm weather turned Riviera’s fairways loose and made the greens almost rock-hard.

“Bill shooting seven under is incredible out there,” Simpson said.

Simpson said the back nine “reminded me of a U.S. Open, just the way the ball is releasing and the temperature got up.”

That has some credibility, as Simpson is the reigning U.S. Open champion.

For the record, the only U.S. Open played at Riviera, in 1948, was won by Ben Hogan.

Haas and Simpson will have plenty of time to chat Sunday in an all-Atlantic Coast Conference final grouping of former Wake Forest Demon Deacons. They will be joined by Schwartzel, a member of Conference SA (South Africa).

Simpson missed Haas by a year in college, but the two players are close friends. Simpson said Haas acted as his big brother when he turned pro.

“He’s really looked after me on tour,” Simpson said.

Simpson will be looking three rungs up at Haas on the leaderboard ladder at the start of the final round. Sunday could be a walk-along coronation if Haas plays the way he did Saturday.

Simpson is banking on Riviera’s increasing trickiness.

“A lot can go wrong in a quick second out here,” he said.

Haas was so four-iron, five-iron, red-iron hot he shot 64 despite starting with a five on the easiest hole — the par-five first.

He described himself as “just plugging along” at two under when he birdied the par-four ninth with a 28-foot putt.

Haas followed with a ho-hum, chip-in eagle on the par-four 10th and then made birdie on the par-five 11th.

He played a seven-hole stretch, from the fifth to the 11th, in six under par. His card looked more like miniature golf: 3-3-3-4-3-2-4.

After “slumming” to five straight pars, Haas added a birdie at No. 17 and had a good birdie look at No. 18 but slid his 11-foot putt just right of the hole.

“Certainly would have like to make that putt on 18 after a nice drive and a nice second shot,” Haas said. “But, overall, very pleased.”

Not very pleased was Bae, who seized his first PGA Tour lead Friday before sinking to a tie for 13th after a five-over 76.

Also fading — although you suspected this might happen — was fan favorite Fred Couples. It’s tough, at age 53, to string magic together on prime PGA Tour real estate, and Couples stands at even par, 12 shots back, after descending rounds of 68-72-73.

Sunday’s focus is squarely on Haas, 30, who has won four times on tour but is still looking for the breakthrough consistency that can raise him to golf’s concierge level.

Haas got very rich two years ago by winning the FedEx Cup grand prize, but he wasn’t happy with his 2012 season, in which the Northern Trust was his only win. He had only three top-10 finishes and missed five cuts in 23 starts.

Haas was an afterthought in the majors, missing the U.S. Open cut, and finishing tied for 37th at the Masters, tied for 32nd at the PGA and tied for 19th at the British Open.

Simpson, his younger colleague, has already bagged his major.

“Had a very disappointed, sour taste in my mouth after the way I finished it off,” Haas said of last year. “I know I’m 30 and I should be mature but I think sometimes out there I’m immature.”

Sunday allows Haas some breathing room with another chance to grow up. He has a three-shot lead on a world-class track with conditions expected to be as tough, or tougher.

Of course he has doubts.

“You know,” Haas said, “it’s very difficult in this game to just pull away from the rest of the field. You’ve only seen a few guys ever really do that. And those guys are like Jack Nicklaus, Tiger Woods, Phil Mickelson.”

Haas is only 30, so it’s not too late to join the club.

chris.dufresne@latimes.com