Joaquin Niemann fired a seven-under 66 to grab the first-round lead at the Tournament of Champions on Thursday.
The Chilean, 21, produced a bogey-free opening round in Kapalua, Hawaii, while making seven birdies.
Niemann made four birdies on the front nine before picking up shots at 12, 15 and 18 and holds a one-stroke lead over Justin Thomas.
"I played really good, hit a lot of good shots, I just missed one green on 16," he told the Golf Channel.
"During the practice round, I knew it was going to be tough, there was a lot of wind on Tuesday especially and today it wasn't that windy and I played great.
"I made a lot of putts and it was my day."
Thomas, the 2017 champion, produced a strong finish, making five birdies on his final eight holes.
Matt Kuchar and Rickie Fowler carded five-under 68s to be tied for third, while a group of five are a shot further back.
Defending champion Xander Schauffele is among them, alongside Tyler Duncan, Matthew Wolff, Patrick Cantlay and Jon Rahm.
A two-time winner of the event, Dustin Johnson is tied for 16th at one under.