Fishburn, McCarthy lead at halfway stage of Sony Open
Fishburn, chasing a first tour title of his career after turning professional in 2018, produced some pinpoint iron play and putting to move to the top of the leaderboard on 10 under through 36 holes at Honolulu's Waialae Country Club.
Teeing off on the back nine, Fishburn made a flying start with birdies on the 12th, 13th and 14th holes before adding two more after the turn to cap a largely flawless round.
"I've hit a lot of fairways and feel really comfortable with the putter," Fishburn said as he looked forward to the weekend.
"First round I made a few long ones and today felt like everything was kind of going where I wanted it to on the greens.
"Feel like I'm rolling the ball really well, so excited for the next two days."
McCarthy, who shot an opening six-under-par 64 on Thursday, overcame a shaky start which featured two bogeys in his opening three holes to move up the leaderboard.
After his early trouble, McCarthy drained five birdies and 10 pars over the remaining 15 holes for a four-under-par 66.
It was a mixed bag for McCarthy, who fluffed short putts for par on the second and third before reigniting his round with a 24-footer for birdie on the fifth.
"Missed some in close today that I'd normally clean up, so that was a little frustrating," McCarthy said.
"Missed a couple short ones early and bounced back. Made some mid- to long-range putts in the middle of the front nine to get me into the round... everything feels really good."
Japan's Kensei Hirata was the biggest mover of Friday's second round, vaulting 41 places up the leaderboard into a three-way tie for third on nine under, one off the pace, after a seven-under-par 63.
Hirata is joined by Americans Eric Cole and Paul Peterson, who followed his opening 64 with a 67 respectively.
Five players -- Austria's Sepp Straka, and Americans Lee Hodges, Alex Smalley, J.J. Spaun, and Zach Johnson are a further shot back on eight under.