Los Angeles - South Korea's Kang Sung, seeking a win to reach his first Masters, birdied four holes in a row before a closing bogey left him one adrift of leader Rickie Fowler after the first round of the Houston Open.
US star Fowler fired a bogey-free eight-under par 64 to seize the lead in the final PGA tuneup event for next week's Masters, the first major championship of the year at Augusta National.
But Kang, whose impressive birdie putt run began with a 14-footer at the third, sank another 14-footer at 17 to match the lead before missing a four-foot par putt at the last, an error he blamed on spike marks.
"Couple spike marks right on my line as I tried to hit a straight putt and went to the right, but except for that played great today," Kang said. "I played pretty solid."
Kang, 29, has never played in the Masters. He shared 18th at last year's US Open in his only major start. He has not won since the 2013 Korean Open.
To reach Augusta, he will have to change that this weekend, but he's not wanting to think too much of the Masters just yet despite opening on 65.
"No. First day just finish," Kang said. "I don't really think about the future very much. Whatever happens, happens."
"I just keep grinding, keep playing well, and just do what I can do the next few days and just accept the result."
Fowler, who began on the back nine, birdied five of his first seven holes and added back-to-back birdies at the third and fourth before closing with a birdie at the par-3 ninth.
"I was fortunate enough to take advantage of the par-3s, played them at 3-under, and I managed my way around nicely with mud balls all day," Fowler said.
"The golf course was gettable, but it's tough when you're playing in those kinds of conditions with mud balls. Not as much when you have wedges in your hands, but once you get some longer irons to potentially woods going for par-5s in two, it becomes a bit dicey."
Sharing third were Americans Kyle Stanley and Stewart Cink and Venezuela's Jhonattan Vegas on 66.
"It was a great round," Vegas said. "From the beginning all the way to the end, I felt like I had a great process going. Shooting 6-under on this course with everything this course brings is always really nice."
Reigning Olympic champion Justin Rose of England was among seven others another stroke off the pace.
Two-time major winner Jordan Spieth and fellow American Jimmy Walker, the 2016 PGA Championship winner, were on 69, while five-time major winner Phil Mickelson, who won at Houston in 2011, opened on 72 and Sweden's Henrik Stenson, the reigning British Open champion, was on 74.
"I played terrible and unfortunately I put myself back quite a bit, but I've been playing well," Mickelson said. "Playing here really helps me to get sharp so that I don't have a day like this next Thursday (at the Masters)."
Leading scores after Thursday's opening round of the US PGA Houston Open (par-72, USA unless noted):
64 - Rickie Fowler
65 - Kang Sung (KOR)
66 - Stewart Cink, Jhonattan Vegas (VEN), Kyle Stanley
67 - Vaughn Taylor, Keegan Bradley, Justin Rose (ENG), Hudson Swafford, Troy Merritt, Russell Henley, Tom Hoge
68 - Harold Varner, Ryan Blaum, Kevin Streelman, Jason Dufner, Aaron Baddeley (AUS), Bryce Molder, Andrew Loupe, Geoff Ogilvy (AUS), Grayson Murray, Billy Horschel, Adam Scott (AUS), D.A. Points, Luke List, Robert Garrigus, Jason Kokrak, Andy Sullivan (ENG), Wesley McClain