Kapalua - Ryan Moore and Justin Thomas shot identical six-under 67s for the second straight day and are tied for the lead at the halfway point of the PGA Tour's Tournament of Champions.
Moore and Thomas are at 12-under 134 and have a one shot lead after 36 holes at the Plantation Course in Kapalua, Hawaii.
First round leader Jimmy Walker is tied for second with Patrick Reid at 11 under, but world number one Jason Day is also still in the mix.
Walker was at 12 under until he made bogey on the 17th hole to fall one back after a 70 on Friday. Reed posted one of the low rounds of the day with an eight-under 65.
Moore closed his round with a wedge shot on No. 18 that stopped a foot from the hole. He made birdie on four of his final five holes.
Thomas put together a string of three consecutive birdies starting at No. 3. His lone bogey of the round came at the par-five No. 15.
Jason Dufner was by himself at 10 under after back-to-back 68s, and Hideki Matsuyama of Japan was another shot back at nine under after a 68.
Matsuyama, who is seeking his fourth straight win, was one of six players to lead in the second round.
Australia's Day was tied for 11th at seven under after posting a 69. American Dustin Johnson was also at seven under after a second-round 70.
Defending champion Jordan Spieth sabotaged his otherwise strong round with a triple bogey after an errant drive on the 17th hole for a 69.
He is seven shots adrift at five under.
"I'll struggle for the next couple hours getting over 17 kind of throwing me out of the tournament," Spieth said.
134 - Justin Thomas 67-67, Ryan Moore 67-67
135 - Patrick Reed 70-65, Jimmy Walker 65-70
136 - Jason Dufner 68-68
137 - Hideki Matsuyama (JPN) 69-68
138 - Tony Finau 70-68, Fabian Gomez (ARG) 70-68, Daniel Berger 68-70, Jim Herman 67-71
139 - Brendan Steele 72-67, Jason Day (AUS) 70-69, William McGirt 70-69, Dustin Johnson 69-70