Kuala Lumpur - American Bronson Burgoon outshone Ryder Cup stars Justin Thomas and Paul Casey as he shot nine-under par 63 to lead the $7 million CIMB Classic on Thursday - and then played down his round as "boring".
At the revamped TPC Kuala Lumpur, the 31-year-old Burgoon chipped in for an eagle on the 18th hole, his ninth after starting from the 10 tee, and then added five birdies on his back nine.
That gave him a one-shot lead over compatriot Austin Cook on a low-scoring first day, with the red-hot Billy Horschel in a three-way tie for the third place at seven-under par.
Thomas, the two-time CIMB champion and former world one, shot four birdies in his last five holes to move to three shots behind the leader, tied sixth at six-under par along with seven other players including England's Casey.
"I drove it well and I putted pretty good, so it was kind of boring golf, but that's always a good thing," said the Texan.
"I chipped in for eagle from the bunker on my ninth hole, which kind of boosted me, then I just kept going."
World number four Thomas, winner of the event in 2015 and 2016, was happy with his start, especially the finish to his round.
"It was a good day. Kind of up and down. I got off to a good start and then kind of stalled out a little bit there in the middle," said the man with eight PGA Tour wins in the last two seasons.
"I hung in there and just really didn't hit my irons very well. I just didn't take advantage of a couple opportunities, but kind of found something there those last five holes and was able to at least make a good round of it today."
Horschel continued from where he left off in the FedEx Cup playoffs, where he finished inside the top-three in four starts and withdrew from the fourth.
Defending champion Pat Perez opened with a two-under-par 70 in the tournament jointly sanctioned by the PGA and the Asian Tours.
Leading first-round scores on Thursday from the PGA Tour's CIMB Classic at the TPC Kuala Lumpur, Malaysia (par 72):
63 – Bronson Burgoon (USA)
64 – Austin Cook (USA)
65 – Scott Piercy (USA), Billy Horschel (USA), CT Pan (TPE)
66 – Nick Watney (USA), Emiliano Grillo (ARG), Kevin Chappell (USA), Justin Thomas (USA), Louis Oosthuizen (RSA), Joel Dahmen (USA), An Byeong-hun (KOR), Paul Casey (ENG)
67 – Shubhankar Sharma (IND), Chesson Hadley (USA), Abraham Ancer (CAN), Kim Si-woo (KOR), JB Holmes (USA), Scott Stallings (USA)
68 – Ernie Els (RSA), Stewart Cink (USA), Kevin Na (USA), Marc Leishman (AUS), Ryan Palmer (USA), Ben Leong (MAS)
69 – Gaganjeet Bhullar (IND), Whee Kim (KOR), Danny Lee (NZL), Ryan Armour (USA), Cameron Smith (AUS), Kiradech Aphibarnrat (THA), Charles Howell III (USA), Gary Woodland (USA), Xander Schauffele (USA)
70 – Thomas Pieters (BEL), Pat Perez (USA), Branden Grace (RSA), Davis Love III (USA)
71 – James Hahn (USA), Satoshi Kodaira (JPN), Peter Uihlein (USA)
72 – Anirban Lahiri (IND), Kyle Stanley (USA), Justin Harding (RSA), Park Sang-hyun (KOR)
73 – Rafa Cabrera-Bello (ESP), Jimmy Walker (USA)
75 – Brandt Snedeker (USA)