American Scott Piercy has built an early two-shot lead at the Safeway Open after shooting a course-record 10-under-par 62 on day one.
Piercy, who is searching for a fourth PGA Tour title, blitzed his way round the course at the Silverado Resort in Napa, making 12 birdies, two bogeys and four pars.
The 37-year-old's sensational performance was largely down to his impressive putting, an area that has taken a massive jump up, having been down at 150th in the stats last year.
He is hoping to continue the recent success on the greens and build on the current two stroke lead when action gets back underway for day two on Friday.
"We've been working on the putter a lot and trying to get some things figured out," Piercy said. "Today was a good start off to the season, a good start to give me some confidence with the putter."
Englishman Paul Casey, who is eyeing a first win on American soil since the 2009 Shell Houston Open, is currently in a two-way share of second alongside Patton Kizzire after both players carded eight-under-par 64's.
The world number 12 missed just one green in regulation whilst his putting was also on song, sinking a 16-foot birdie putt from the fringe on the second hole.
American pair Johnson Wagner and Kyle Stanley both signed for rounds of 65, leaving them on -7, Jon Rahm produced a moment of magic on way to a six-under 66.
The Spaniard, joined on that mark by Troy Merritt and Bill Haas, hit a hole in one at his second hole, the par-three 11th, and described the ace as a "very special moment".