Paul Casey maintained his impressive form on the PGA Tour by posting an opening-round 65 to sit one shot off the lead at the CIMB Classic.
The 39-year-old, who is chasing a first PGA Tour win since 2009, birdied four of his final five holes in Kuala Lumpur to stay in touch with early pacesetters Justin Thomas, Derek Fathauer and Keegan Bradley.
Casey dropped his only shot of the day on the par-five third but posted gains at the fifth, seventh and ninth to reach the turn two under.
The Englishman continued his strong start by picking up shots at the 11th and 14th before finishing with three successive birdies, while defending champion Thomas also posted a back-nine 31 on his way to being part of a three-way tie at the top.
"It was a good day, it was solid," Thomas said. "If there's any such thing as an easy eight under, that was it. I hit it real close and made a few putts, so it was a pretty low-stress day."
Fathauer posted a bogey-free 64 to also share the early advantage, with Bradley completing the trio after posting six birdies on the front nine.
An eagle-three at the next cancelled out blemishes at the 11th and 13th, before back-to-back birdies along the closing stretch lifted Bradley back to the top.
Anirban Lahiri sits two strokes off the pace after finishing his six-under 66 with successive blemishes, with Sergio Garcia part of the four-man group a further shot back following a blemish-free start.
Australian Adam Scott, who finished a stroke behind winner Thomas last year, started with a two-under 70 while England's Ian Poulter, on his return from a foot injury, is a shot further back.
Watch the CIMB Classic throughout the week live on Sky Sports 4 - your home of golf. Live coverage continues on Friday from 3.30am.