SEOUL (Reuters) - Justin Thomas made a slow start to the PGA Tour's CJ Cup in South Korea on Thursday with a bogey at his opening hole but the FedExCup champion soon caught fire, carding seven birdies and a pair of eagles in a nine-under round of 63 to lead the way.
Thomas ended the day three strokes clear of Marc Leishman, Patrick Reed and three other players in the opening round of the PGA Tour's first regular event in Korea, which is being played at the Nine Bridges course on the resort island of Jeju.
Former world number one Jason Day is five strokes adrift after carding a four-under 68, while Paul Casey and Adam Scott carded matching even-par 72s in the third event on the 2017-18 schedule.
Kim Whee was the pick of the home players with a 68, with veteran K.J. Choi a shot further back. Bae Sang-moon continued his comeback from two years away from the game to fulfil his military service obligations with a one-under 71.
Shrugging off a dropped shot at his first hole, the 10th, Thomas eagled the 12th and birdied 14 before moving to three under by holing out from a greenside bunker at the 15th.
The PGA Championship winner picked up further shots at the 16th and 17th before grabbing his second eagle in eight holes at the 18th.
The 24-year-old American's second nine holes were sedate by comparison, with just three birdies and a bogey, though he finished on a high by picking up a stroke on the ninth.
"On that last nine holes I felt like I had a really good opportunity to shoot something really, really low so that was a little bit of a bummer," he said.
"If I would have parred the my last hole, I would have had a pretty sour taste to my mouth walking off the golf course."
Thomas capped his terrific 2016-17 campaign by being crowned FedExCup champion, and picking up the $10 million bonus that goes with it, before helping the United States maintain their grip on the Presidents Cup.
While he struggled with his wedge play on occasion on Thursday, Thomas was happy with his driving but said he was not focusing too much on technique.
"I just swing about as hard as I can a lot of times I hit a driver," he said. "When I'm driving it well it usually goes pretty far and straight, so that's all I'm trying to do right now."
(Reporting by Peter Rutherford; Editing by John O'Brien)