Los Angeles - South Korea's Kim Si-woo birdied five of his last eight holes on the way to a six-under par 66 and a one-stroke lead after the first round of the US PGA Tour Texas Open on Thursday.
Kim, who won the most recent of two US PGA titles at the 2017 Players Championship, had eight birdies total at on the Oaks course at TPC San Antonio where a crowded leaderboard saw Venezuela's Jhonattan Vegas, Mexico's Abraham Ancer and Americans J.T. Poston and Brian Stuard just a shot back.
Three-time major winner Jordan Spieth and fellow American Rickie Fowler were two adrift in a group that also included New Zealand's Danny Lee, Mexico's Roberto Diaz and Americans Ted Potter, Scott Stallings, Morgan Hoffman, Ryan Moore, Chris Stroud, Max Homa and Hank Lebioda.
Kim teed off on 10, and started to warm up with birdies at 14, 17 and 18.
After a bogey at the first, Kim birdied five of his next six holes -- draining a 19-footer at the par-three third.
While he was dialed-in on the greens, Kim said solid iron play on his back nine was the key.
"That's why I get closer to the pin," the 23-year-old said.
Fowler, coming off a two-week break, was pleased to "shake off some rust" in the last tournament before the year's first major, the Masters, tees off at Augusta National next week.
"Happy with where we're at going into tomorrow, but also looking forward to the weekend with some work to do tomorrow as well as how I feel about the game going into next week," said Fowler who had five birdies and a bogey in his 68.
"Really only one blemish, the tee shot on our 17th hole, number eight, but other than that, solid day of golf and some good work."
Spieth is hoping for a confidence-boosting performance going into the Masters, with a best finish so far this year of tied for 35th.
The American, who said last week at the WGC-Match Play that he was going in the right direction, also had five birdies and a bogey in his 68.
"Stroke feels good," Spieth said.
"Struggled a little with the swing to start, just didn't hit a whole lot of fairways," added the American, who hit just five of 14 fairways in regulation.
"There's no rough out here right now unless you get outside of the primary rough, so you can hold greens from that rough but it's very difficult to get it close to the hole locations to get more birdie chances," Spieth said. "So certainly looking to ramp up those fairway numbers to give myself maybe more looks at potentially more birdies."