San Antonio - Charley Hoffman fired five birdies in a five-under par 67 on Thursday to take the lead by one shot after the wind-whipped first round of the US PGA Tour Texas Open.
Australia's Aaron Baddeley also had five birdies with one bogey in a four-under 68 at TPC San Antonio.
He was one stroke in front of American Max Homa, who closed with back-to-back birdies to grab sole possession of third place on a three-under par 69.
Five-time major winner Phil Mickelson was tied for fourth with 70, despite an equipment malfunction that saw the head of his eight-iron break off on a shot from a fairway bunker.
He was joined at two-under by fellow American Ryan Palmer, whose round included an eagle and a double-bogey.
Only 12 golfers broke par as the gusty winds pushed scores up.
"It was really challenging, really difficult," said American Matt Kuchar, who was happy to get off the course after an even par 72 - more than six strokes better than the morning scoring average of 78.61.
US Open champion Martin Kaymer of Germany had two triple bogeys in an 82, while defending champion Steven Bowditch of Australia opened with an 80.
Hoffman's bogey-free effort looked even more impressive under the circumstances, although he did benefit from playing later in calmer winds.
He hit eight of 14 fairways in regulation and needed just 24 putts.
Baddeley's round included an unlikely birdie at the par-four 17th, where he hit his tee shot into the woods, took an unplayable lie and went back to the tee.
His second effort went straight, and as he started walking he heard the gallery roar - his third shot had gone in for a birdie three from 336 yards.
"I just thought I'd just hit it straight and so I hit it and started walking and then heard the crowd going nuts," he said. "it was like, 'wait, I just made birdie.'"
Baddeley also played in the afternoon, but he had prepared himself for difficult conditions.
"I knew it was going to be blowing," he said. "Even going to bed last night I already had the mindset, I just had to be patient."
Mickelson birdied three of his final five holes, but the most attention-getting moment of his round came at the par-four 12th, where the head of his eight-iron came off as he hit out of a fairway bunker, leaving him holding the shaft.
"It was just a weird thing," Mickelson said. 'I'm just curious at what point on the downswing it came off, if it was right before impact or right at impact, because the shot didn't come off very well."
With the Masters just a fortnight away, Northern Ireland's Graeme McDowell opted to play it safe and withdrew after nine holes because of a nagging ankle injury.
Two-time PGA Tour winner Bae Sang-Moon of South Korea also withdrew with a back injury and American Colt Knost pulled out with a wrist injury."Leading first-round scores on Thursday in the US PGA Tour $6.2 million Texas Open (USA unless noted, par-72):
67 - Charley Hoffman
68 - Aaron Baddeley (AUS)
69 - Max Homa
70 - Phil Mickelson, Ryan Palmer
71 - Cameron Beckman, Daniel Summerhays, Jordan Spieth, Jimmy Walker, Chris Kirk, Zach Johnson, Chesson Hadley
- Cameron Percy (AUS), Matt Kuchar, Park Sung-Joon (KOR), Kevin Na,
Billy Horschel, John Merrick, Scott Piercy, Jason Kokrak, William
McGirt, Fabian Gomez (ARG)
73 - Brian Davis (ENG), Jerry Kelly,
Kevin Chappell, Brendon Todd, Michael Thompson, Bryce Molder, John Huh,
Scott Pinckney, Thomas Birdsey