Los Angeles - American JT Poston equalled the course record with a 10-under-par 62 to grab a slim lead after the first round of the PGA Tour's Barbasol Championship.
The 26-year-old delivered 11 birdies and one bogey at Keene Trace Golf Club's Champion course.
Canada's Nick Taylor is one shot back after firing 63 and Wes Roach is alone in third with a 64.
Kelly Kraft, Kramer Hickok, D.J. Trahan, Roberto Castro, Jim Herman, Bill Haas, Josh Teater and Colombia's Sebastian Munoz are tied for fourth at seven under.
Poston made a half dozen birdies on his first eight holes before carding his lone bogey on the par-three ninth hole.
"It was one of those days, everything clicked and I was hitting it so good, I didn't have that many lengthy birdie putts I made until the last hole," Poston said. "I kind of hit it like that the last month or so and had a couple of good rounds.
"Lot of rain last night, so (the greens) are soft and they are really good greens and you can make a lot of putts. They are rolling really well."
Taylor, of Winnipeg, said the overnight rains helped him shape his game.
"I hit every green, I didn't miss a fairway, so it was very solid tee to green and putts were going in," Taylor said. "Everything was kind of clicking today. With the soft conditions, it was different than the practice rounds.
"I thought it would be a little bit more difficult, and then that rain came in last night and definitely softened things up. "
John Daly, who pulled out of this week's Open Championship a week ago after being denied the use of a golf cart due to a medical problem, shot a one-under 71 on Thursday.
Leading scores after Thursday's first round of the PGA Tour's Barbasol Championship (par-72, USA unless noted):
62 - JT Poston
63 - Nick Taylor (CAN)
64 - Wes Roach
65 - Juan Sebastian Munoz (COL), Kelly Kraft, Kramer Hickok, D.J. Trahan, Bill Haas, Roberto Castro, Jim Herman, Josh Teater
66 - Matt Jones (AUS), Anders Albertson, Ricky Barnes
67 - Cameron Davis (AUS), Satoshi Kodaira (JPN), Fredrik Jacobson (SWE), Daniel Chopra (SWE), Dominic Bozzelli, Tom Hoge, Denny McCarthy, Jason Dufner, Will MacKenzie, Kyle Jones, Austin Cook, Chase Wright