Justin Thomas goes 8 under during 7-hole stretch en route to 63

JEJU, South Korea -- Justin Thomas had two eagles on his front nine and finished with a 9-under 63 to take a 3-stroke lead Thursday after the first round of the CJ Cup at Nine Bridges, the first official PGA Tour tournament staged in South Korea.

Thomas started with a bogey at No. 10 but made amends with eagles on the par-5 12th and 18th holes around four straight birdies on Nos. 14-17 to turn in 29. He added three more birdies and a bogey to hold his margin.

"It was kind of a weird day,'' Thomas said. "It started off with a really, really bad bogey. And then I had a seven-hole stretch there where I basically kind of went unconscious. That was pretty much most of my round.''

Thomas has won the CIMB Classic in Malaysia twice -- in 2015 and 2016 -- and says he is comfortable playing overseas.

"It's still golf,'' Thomas said. "It doesn't matter where you are, and I know that it is very cliche and easier said than done, but you just have to take advantage of the rest and time you have off the course.''

Chez Reavie, Gavin Kyle Green , Scott Brown, Patrick Reed and Marc Leishman all opened with 66s and were in a five-way share of second at 6 under.

Jhonattan Vegas and Charles Howell III were among five players a shot further back at 5 under.

Jason Day and fellow Australian Rod Pampling were at 4 under, one stroke ahead of Pat Perez, who was coming off a victory at last week's CIMB Classic in Malaysia. Adam Scott had a 72 in his opening round, with four birdies and four bogeys.