Justin Thomas posted a flawless eight-under 64 to erase a four-shot overnight deficit and secure back-to-back CIMB Classic titles.
Thomas finished the tournament 23-under at TPC Kuala Lumpur, three shots ahead of Japan's Hideki Matsuyama, whose final-round 66 was not enough to keep up.
Both of 23-year-old Thomas' two PGA Tour wins have been at the CIMB Classic.
Thomas also put in a solid showing at last week's Safeway Open, the PGA Tour's season-opener, finishing just four strokes off the lead.
"I feel like I just need to continue to build on this momentum and try to use this as kind of a springboard to the start of the year," he said. "To try to move up in the world rankings and get in that top 10, get in that top five."
Widely regarded as one of golf's up-and-coming young players, Thomas' deft wedge play and approach shots were a major plus in Malaysia's hot and humid conditions, which were ideal for scoring.
Thomas said he especially drew confidence from being able to lead the first two rounds and come back for the win after faltering in round three. On Saturday he was cruising toward the title when he dropped four shots in a three-hole stretch to start the back nine.
That put India's Anirban Lahiri in the driver's seat with a four-stroke lead coming into the final round.
But on Sunday it was Lahiri's turn to falter, stumbling on the par-five third hole with a quadruple-bogey nine after his errant tee shot got stuck in a tree, forcing him to take a penalty and return to the tee.
Although he clawed back with a birdie and an eagle on the next two holes, a bogey quickly followed and failure to convert putts down the stretch sealed his fate.
"I fought back as best I could, but I just couldn't get the putts to fall on the back nine," he said, calling the outcome a "tough pill to swallow".
Lahiri, the 2015 Asian Tour Order of Merit winner, ended up tied for third at 19-under with Derek Fathauer of the United States, with Australia's Marc Leishman two strokes further back.