Dustin Johnson made 10 birdies and tied the course record with a 9-under 63 to build a five-shot lead in the HSBC Champions.
Johnson put himself in great position to start another PGA Tour season with a win. He won the Tournament of Champions in Hawaii last January. This World Golf Championship is his first tournament of the 2013-14 season.
Starting four shots behind, Johnson overpowered Sheshan International with pure, powerful tee shots. He birdied six of the opening seven holes and finished at 12-under 132.
Rory McIlroy reached 10-under at the turn, but struggled on the back nine and had to settle for a 72. He was five shots behind, along with Boo Weekley and Bubba Watson.
Phil Mickelson had a 68 and was seven shots behind.