Thomas won his first and only PGA Tour title at the $7 million co-sanctioned event a year ago and the American backed up his opening round 64 with some flawless golf to lead the way heading into the weekend on 14-under for the tournament.
"I didn't play as well as I did yesterday. I drove it better, which was good, but I definitely had a couple iron shots and a couple wedges that I felt like I should have hit closer, but bogey-free is always good," Thomas told reporters.
Anirban Lahiri is alone in second place after firing a second straight 66 but the Indian repeated the late lapse he suffered on Thursday to fall out of a tie for the lead when he stumbled over the line with a double-bogey seven at the last.
Russell Knox recorded the best round of the day to move into a tie for third place on 11-under alongside James Hahn and Hideki Matsuyama, the America-based Scot signing for a flawless nine-under-par 63 to surge 23 places up the leaderboard.
Joint overnight leader Derek Fathaeur dropped into a tie for sixth place after a two-under 70, while fellow American Keegan Bradley (72) fell two shots further back in the second event of the wraparound 2017 PGA Tour season.
Thomas set the tone for his round with four birdies on his opening seven holes and while he only managed to pick up two more shots coming in, the 23-year-old has only recorded one bogey in 36 holes and looks a good bet to defend his title.
"I'm just going to try to do the same thing. Just going to try to hit fairways and from there, I'll be able to attack because I'll have short-scoring clubs," Thomas added.
"Out here, you have to make a lot of birdies to get closer to the lead or build a lead, so I'm just going to try to keep doing the same thing and make a lot of birdies."
The event is co-sanctioned by the Asian Tour.
(Writing by John O'Brien in Singapore; Editing by Sudipto Ganguly)
