HONOLULU, 17 Jan, 2015 (AFP) - The 21-year-old American vaulted up the leaderboard with a nine-under 61 but it was his final three holes -- where he went birdie, birdie, eagle -- that had the Waialae Country Club buzzing on Friday.
"I'm excited. It's a position I haven't been in before and I think that kind of comes with the territory of being a rookie," said Thomas. "I'm going to hopefully find myself in a lot of positions this year."
First round co-leader Webb Simpson shot a four-under 66 and Matt Kuchar carded a seven-under 63 to join Thomas at the top of the leaderboard with a 12-under 128.
They have a two-stroke lead on Troy Merritt (64) and Tim Clark (65) who are both tied for third at 10-under 130. Scotland's Russell Knox (65) and Rory Sabbatini of South Africa (67) are at nine-under.
Paul Casey, who was tied with Simpson after round one, managed to shoot an even-par 70 and he is tied for eighth with defending champion Jimmy Walker (66), Marc Leishman (62), Ryan Palmer (63), J.J. Henry (67) and Robert Streb (69) at eight-under 132.
Thomas started on the back nine with six straight pars. The birdies then started to fall and by the time he reached No. 7 on his back nine he was at eight-under for the tournament.
He drained a 12-foot birdie putt on the par-three seven and followed it up with another birdie on No. 8. On the par-five ninth, he reached the green in two and then rolled in the long eagle putt to pull even with playing partners Simpson and Kuchar.
World number 11 Kuchar sandwiched a birdie on the 16th in between four pars to finish up his round.
"I drove it really well and when you drive it well the course becomes much more attackable," said Kuchar, 36. "It was a much better ball-striking round for me and I've continued two days of really good putting."
US Open champ Simpson had three birdies over his final five holes.
"It felt good," said Simpson, who is using a conventional putter for the first time as a Tour professional after ditching his belly putter.
"I've been nervous to get started this season using a short putter, but just thankful. Thankfully I'm 12-under and have had a good start."
Second-round scores in the $1 million USPGA Sony Open on Friday (par-70):
128 - Matt Kuchar 65-63, Webb Simpson 62-66, Justin Thomas 67-61
130 - Tim Clark (RSA) 65-65, Troy Merritt 66-64
131 - Rory Sabbatini (RSA) 64-67, Russell Knox (SCO) 66-65
132 - J.J. Henry 65-67, Paul Casey (ENG) 62-70, Jimmy Walker 66-66, Ryan Palmer 69-63, Marc Leishman (AUS) 70-62, Robert Streb 63-69
133 - Kevin Na 66-67, Brian Harman 66-67, Camilo Villegas (COL) 63-70, James Hahn 69-64, Chris Kirk 66-67, Daniel Summerhays 66-67