World number two Jon Rahm opened a two-stroke lead at the Mexico Open on Friday, firing eight birdies in five-under-par 66 for a 36-hole total of 12-under 130 at Vidanta Vallarta.
The Spanish star, the highest-ranked player in the field of the long-established event that is part of the US PGA Tour for the first time this year, steered a steady course in more difficult conditions to break free atop the leaderboard after sharing the overnight lead with five others.
"Today was a bit more of a grind, but still a really good round of golf," said Rahm, who had a two-shot lead over American Alex Smalley.
Smalley had an eagle and five birdies in his five-under-par 66 for 132. He was one stroke in front of Americans Adam Long, Andrew Novak, Cameron Champ, Patrick Reed, Trey Mullinax and Brandon Hagy.
Former Masters champion Reed, Long and Champ all carded five-under-par 66s. Novak and Hagy signed for 67s and Mullinax shot 69.
Rahm rolled in a 28-foot birdie putt at the first hole, but promptly gave a shot back with a bogey at the second. After birdies at the third and sixth his "perfect" six-iron at the ninth left him a three and a half-foot birdie putt that saw him make the turn at 10-under.
"I think my iron game was really, really good today," Rahm said. "It was really under control and in those windy conditions I was hitting it really, really solid so, I was never really too surprised where my ball was ending up and I was always in a good position.
"That's probably why I had so many birdie looks out there today."
After a bogey at the 10th, Rahm rolled in a 14-foot birdie at the 12th, a three-footer at 14 and an eight-foot birdie at the 15th. He followed his third bogey of the day at 16 with a par save from a greenside bunker at the par-three 17th and a six-foot birdie at the 18th.
"I can't really complain about anything I'm doing right now, so hopefully I can keep that good ball-striking going and keep rolling it the way I have," said Rahm, who is seeking his first title since he won his maiden major at the US Open at Torrey Pines last year.
Smalley, a 25-year-old in search of his first US PGA Tour title, eagled the par-four third and picked up three birdies on the front nine to make the turn five-under.
He had two bogeys and two birdies on the back nine, played in increasingly challenging wind.
"It was hard, it certainly was," Smalley said. "I was able to keep the ball in play and was able to get out of those holes that were playing really long, and happy I'm done with them."