(Reuters) - Boosted by extra work spent on his putting last week, Ben Crane fired a sparkling nine-under-par 63 to surge into a tie for the second-round lead in the Humana Challenge at La Quinta, California on Friday.
The 35-year-old American birdied two of his last four holes on the Palmer Private course at PGA West, one of three venues hosting the pro-am celebrity event, to post a 16-under total of 128.
That put him level with compatriots David Toms (65) and Mark Wilson (62), who also took advantage of near-perfect scoring conditions on another sun-splashed day in the California desert.
PGA Tour rookie Harris English was a further three strokes back after matching Wilson with a best-of-the-week 62 to finish alongside fellow Americans Chris Kirk (63) and Bobby Gates (63), plus Colombian Camilo Villegas (68).
Crane, who won his fourth PGA Tour title at last year's McGladrey Classic, was delighted with his score after making a few tweaks to his game since the end of last season.
"We made a couple of little adjustments with my swing, a couple of shoulder alignment things, and it's freed me up with the full swing," Crane told reporters after totaling just 22 putts.
"And then my putting coach came in last week and we worked on seeing the line and hitting my line with the putting and I was able to do that.
"I made a lot of 10 and 15-footers, and all my kind-of-close putts for birdie. I putted extremely well and every part of my game felt great. I guess that's how you do it."
Toms soared into a share of the lead with a stunning birdie-eagle-birdie finish, having launched his round on the Nicklaus Private course with a birdie at the par-four 10th.
"I started to hit some better shots, hit some good putts that didn't go in and then made a few and then finished great," the 44-year-old said. "I turned just a so-so day into a pretty solid day.
"I knew that I was playing well, it was a matter of time where I would start making some birdies and I finished really strong. So I just stayed patient all day."
While most of the players in the 144-strong field were well under par after two rounds in ideal weather conditions, twice champion Phil Mickelson was a distant 15 strokes off the pace.
Making his first appearance of the year on the PGA Tour, the American world number 15 carded an up-and-down 69 that featured seven birdies, two bogeys and a double-bogey to finish at one under.
Level with Mickelson was Australia's former world number one Greg Norman, who is playing in the $5.6 million event for the first time since 1986 after being persuaded to return by former U.S. president Bill Clinton.
Norman followed his opening 72 with a 71 and will play in Saturday's third round in the high-profile company of Clinton, whose charitable William J. Clinton Foundation is a hosting tournament partner this week.
Venezuelan Jhonattan Vegas, who won last year's title in a playoff with Americans Bill Haas and Gary Woodland, was at two under after returning a level 72 at LaQuinta Country Club.
American world number eight Dustin Johnson, the highest-ranked player in the field, withdrew from the tournament midway through Friday's second round due to a lower back injury.
(Reporting by Mark Lamport-Stokes in Los Angeles; editing by Julian Linden)