The Mexican player holed a 100-yard wedge shot for eagle at his first hole and never looked back as he blitzed the TPC Deere Run course in Silvis with a nine-under-par 62, to lead Americans Adam Long and Russell Henley by two.

The 32-year-old Diaz had seven birdies to go with the eagle in a flawless, bogey-free round.

"I just feel that everything clicked," Diaz said. "I've been playing pretty solid throughout the year. The driver has been awesome. I've been hitting a lot of fairways, and today I hit good numbers all day, and that helps."

Winless on the PGA Tour, Diaz tied for eighth at the Travelers Championship last month.

Long, who got his first career win earlier this season at the Desert Classic, had eight birdies – four on the front nine and four on the back nine.

Henley has missed the weekend cuts in his last four straight starts. But he highlighted an impressive birdie run by drilling a 55-foot putt on the par-3 7th hole.

"I don't think I've ever lost the belief that I can have a nice tournament," Henley said. "It's just a matter of a few bumps here and there."

RIGHT: Henley trails by two shots after the opening round of the John Deere Classic. PHOTO: Dylan Buell/Getty Images.

Twenty-year-old rookie Matthew Wolff, who picked up his first career win at the 3M Open last week, opened with a 67.

Wolff, the youngest winner on the tour since Jordan Spieth won at Deere Run six years ago, hit 15 greens in regulation and played bogey-free.

"Having that PGA Tour card locked up is a lot of weight off of my shoulders," Wolff said. "Everything in my game feels really good right now."

Davis had five birdies to go with an eagle-three at the par-5 2nd hole, but bogied the subsequent hole to end the round tied 10th.

Compatriot John Senden was a shot further behind and in a tie for 20th, while Steve Allan (two-under) and Matt Jones (even) were the next best Australians.

There is plenty of incentive for many in the field, including Davis and Senden, with the winner earning a berth at next week's Open Championship.