Charley Hoffman and Rico Hoey shot a pair of 63s to make the halfway mark at The American Express at La Quinta Country Club in California.
Hoffman birdied five of his final seven holes on the Nicklaus Tournament course – one of three used for the event – with Hoey making eight birdies in 10 holes from the fourth on the same layout.
Hoffman, who included two eagles in his round, is chasing his first PGA Tour win since 2016 after struggling with back problems in recent years.
“Three years ago, I wasn't very healthy and I wasn't a very good golfer,” Hoffman said.
“I feel good at the moment. Like I said, I could wake up in the morning and feel completely different.
“When I'm healthy, it's warm weather, I feel like I can beat anyone in the world. When it's cold and my back is bad, I don't think I can beat anyone in the world.”
Hoey added: “It's my second year on the tour, so I'm still kind of in awe of a lot of those guys, Hoffman, Cantlay, Rickie and others.
“It's really cool for me to just put my name out there and keep up with them, so that's all I'm trying to do.”
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The pair tops the leaderboard at 16 under, one ahead of Austrian Sep Straka, American Mark Hubbard – who both had 64 on the Pete Dye Stadium course – and compatriot Justin Lower.
Australian Jason Day and American JJ Spawn are further back, followed by a 13-under group that includes Nick Taylor, winner of the Sony Open last week, and Rickie Fowler, who shot a 62 on the Nicklaus course.
Watch the third round from The American Express live on Sky Sports Golf on Saturday at 7pm. Pursue the PGA Tour, majors and more with NOW