Brian Harman produced the round of the day at the Sony Open with a seven-under 63 to open up a halfway three-stroke lead in Hawaii.
The American, world No 23, began Friday a shot off the lead held by countrymen Zach Johnson and Chris Kirk but moved clear of the pack, with five players tied at 10-under in nearest pursuit, thanks to six birdies and an eagle at the par-five ninth.
Harman, who shared the 36-hole lead at last week's Sentry Tournament of Champions at Kapalua, carded three successive birdies from the second hole, during his back nine, before closing his round at Waialae Country Club with a 17-foot eagle putt.
Johnson produced a three-under 67, which saw the two-time major winner mix three birdies, one eagle and two bogeys as he stayed in the hunt for a first professional victory since his victory in The Open, at St Andrews, in 2015.
The 41-year-old five-time Ryder Cup player is joined at 10-under par by unheralded compatriots John Peterson, Tom Hoge and Talor Gooch while four-time PGA Tour winner Kirk is also in contention at the same mark.
Kevin Kisner and Xander Schauffele made strong moves up the leaderboard on Friday, both carding a six-under 64, to move to eight-under - one shot behind American trio Patton Kizzire, Ollie Schniederjans and Kyle Stanley.
Defending champion Justin Thomas, world No 4, recovered from three bogeys during his back nine to finish with a succession of strong putting - two for birdie and one for eagle - to finish at six-under - the same mark as Marc Leishman and Jason Dufner.
Jordan Spieth, who suffered a quadruple-bogey on his penultimate hole in the opening round, recorded a two-under 68 to move to three-under for the tournament but was able to celebrate a 90-foot birdie at the par-four fifth.
The three-time major winner, playing alongside Schauffele and Daniel Berger, mixed four birdies with two eagles on a day of good scoring conditions.
Live PGA Tour Golf
January 14, 2018, 12:00am