Phil Mickelson learned as a junior golfer to never underestimate anyone, no matter the size of his lead or the pedigree of his opponent.
And while the odds of Lefty finally winning in Los Angeles looked good as ever Saturday at the Northern Trust, where he shot a 1-under 70 for a one-shot lead over another former Arizona State golfer - Jeff Quinney - two holes showed how much work remains to add Riviera to his West Coast collection of trophies.
One came at the fabled par-3 sixth, where Quinney hit a 7-iron that he thought was headed for the bunker in the middle of the green, only to land just to the right and roll back into the cup for an ace. The other came at the end of the third round when Quinney holed a 35-foot birdie putt to close the margin to one stroke with his 67.
"If the guy is good enough to be in the last group, he's obviously playing well enough to win," Mickelson said. "I know that I won't be handed anything tomorrow. I know how well Jeff is playing. And I know that there are guys that are right there and can shoot a low round tomorrow. It's my job to go out and hit solid shots."
Mickelson was at 11-under 202, and Quinney might be the only guy he has to worry about.
John Rollins lost momentum with consecutive bogeys and shot 69, leaving him five shots behind.
Scott Verplank overcame a four-putt from 30 feet on the fringe at the par-5 first for a 71 that put him at 208, along with Stuart Appleby (69) and Vaughn Taylor (71).
A year ago, Mickelson had a one-shot lead over Padraig Harrington with five experienced players separated by only three shots. He wound up losing in a playoff to Charles Howell III.
"I like it better this time," Mickelson said.
And well he should.
Mickelson has 32 career victories, 15 of those coming in every West Coast Swing city but Los Angeles. He is 18-7 when he has at least a share of the lead going into the final round.
"Other than Tiger, he's probably the next best front-runner," Verplank said. "He's awful good."
Quinney, a former U.S. Amateur champion who took five years to reach the PGA Tour, has held the 54-hole lead only once, last year in Phoenix, and bogeyed the last two holes to finish third.
"He's going to bring a lot to the table," Quinney said.
"I have to bring my best to the table."
Tom Jenkins moved into position to become the 18th player 60 or older to win a Champions Tour event, shooting an 8-under 64 to take a two-stroke lead over five players in The ACE Group Classic in Naples, Fla.
Jenkins, 60, is 12 under after two rounds at Quail West after an eagle on the 527-yard, par-5 13th, hitting a 2-iron from 236 yards to 28 feet.