Camilo Villegas chipped in for his ninth birdie of the day at his final hole Thursday to cap a six-under 64 and take a two-shot first-round lead in the US PGA Tour Texas Open.

The Colombian was even through two at TPC San Antonio after an opening bogey at the 10th followed by a birdie at 11.

After tapping in for a birdie at 14, Villegas really heated up with a run of six birdies in seven holes: back-to-back birdies at 17 and 18 and four in a row from the second through the fifth.

"Some days the hole is a little bit big and that was the case today," Villegas said. "I played really good, but I also got a couple nice breaks. Made a couple good par saves and overall it was very solid."

Villegas said he "got really lucky" with his birdie at the ninth.

"I hit a chip that was probably going off the green and hit the pin and goes in," said Villegas, who was two strokes clear of South Korean Kang Sung and American Cameron Tringale who shared second on 66.

Former world number one Jordan Spieth headlined a group on five-under 67 alongside Japan's Hideki Matsuyama and South Korean Noh Seung-yul.

"I'm excited," said Villegas, who claimed the last of his four US PGA Tour titles at the 2014 Wyndham Championship. "But it's only Thursday, so we've just got to keep patient, keep doing what we're doing and have fun out there."

Kang, seeking a second US PGA Tour title after his win in the 2019 Byron Nelson, rolled in a 30-foot eagle putt at the second to move to reach three-under for his round.

He added a birdie at the sixth before a birdie-birdie finish at the eighth and ninth.

"I made a lot of putts today," said Kang, who rolled in a nine-footer at the eighth and a 22-footer at his final hole.

Short game boosts Spieth

Spieth, without a victory since his third major title at the 2017 British Open, continued to show he's returning to form with the Masters looming next week.

The American teed off on 10 and seized an early lead with three birdies in his first five holes.

"Felt like I played some really nice golf on our front nine, the back nine," said Spieth, who finished with seven birdies total and two bogeys. "Then just kind of got a little loose off the tee on the front nine, our second nine, and was able to kind of make do. 

"I hit some decent drives, ended up in iffy spots," Spieth added. "Overall, just chipped and putted really well, which was the difference maker today."

Phil Mickelson's Masters tuneup got off to a rocky start that included a quintuple bogey 10 at the par-five 18th.

The five-time major winner was in the fairway off the tee but found the creek with his second shot.

Mickelson's fourth was in the penalty area on the opposite bank of the creek -- where he whiffed on attempt to hit out.

The final tally matched his second-highest score on a hole in his tour career and contributed to a seven-over 79.