Brooks Koepka fired an eight-under 64 to open up a one-shot lead after the opening round of the WGC-HSBC Champions in Shanghai.
The US Open champion mixed seven birdies with an eagle and a sole blemish at Sheshan International Golf Club to edge ahead of nearest challengers Kiradech Aphibarnrat and Gavin Green.
Aphibarnrat struck 10 birdies - including seven in a row around the turn - to grab a share of second, with Green alongside him after carding a blemish-free 65.
Beginning on the back nine, Koepka followed a birdie at the 14th with back-to-back gains from the 16th and added a 20-foot eagle at the 18th to reach the turn in 31.
Koepka nudged in from close range at the first but three-putted from inside four feet to bogey the third, only to bounce back with birdies at the fourth, seventh and eighth to set the target.
"I felt like I played really well," Koepka said. "I drove it pretty well and putted extremely well, except for one little hiccup. The game feels good and I'm excited to start the season."
Three birdies over the last four holes saw South Africa's Haydn Porteous get to six under alongside Patrick Reed, who finished his bogey-free round with a hat-trick of gains.
"There was a couple out there I felt like I left but all in all just a really solid, steady day," Reed said. "Any time you go out and shoot in the 60s in your first round at an event is always good."
Paul Dunne opened with a 67 to join Justin Rose, Tony Finau, Ashun Wu and Matt Kuchar three off the pace, while world No 1 Dustin Johnson lies in the group on four under.
Only 18 of the 78-man field ended the day over par in good scoring conditions, with defending champion Hideki Matsuyama bogeying the last to close a two-under 74.
Watch the WGC-HSBC Champions throughout the week live on Sky Sports Golf. Live coverage continues on Friday from 3am on Sky Sports Golf and Sky Sports Main Event.