Rio Grande, Puerto Rico (SportsNetwork.com) - Mark Hubbard opened with a 4- under 68 on Thursday as he grabbed a 1-stroke lead after the opening round of the Puerto Rico Open.

Hubbard, who is making his 11th start of the season, has just one top-20 finish to his credit. He shared 20th at the Humana Challenge.

Billy Mayfair, a five-time PGA Tour winner, carded a 3-under 69 at Trump International Golf Club. He was joined in second place by Chris Smith and Emiliano Grillo.

Former world No. 1 David Duval headlines a group of 11 players at minus-2. He stands alongside J.J. Henry, Jonathan Byrd, Rod Pampling, Dicky Pride, Alex Cejka, James Driscoll, Chad Collins, Rafael Cabrera-Bello, Jon Curran and Scott Pinckney.

Hubbard played the back nine first on Thursday and he opened with a pair of pars. He traded a birdie at the 12th for a bogey at No. 13. After four more pars, Hubbard birdied the par-5 18th to make the turn at minus-1.

The 25-year-old parred the first three holes of his second nine. Hubbard moved to minus-2 as he birdied the par-4 fourth. He followed with birdies at five and six.

Hubbard faltered to a bogey on the par-3 eighth, but he bounced back with a birdie at the ninth to grab the lead.

"It played tough out there with the wind, but I hit a lot of really good kind of three-quarter and half shots into the wind. I actually probably played the into-the-wind holes better than the downwind holes, where I had to just hit normal shots," Hubbard explained. "But I drove it pretty well, kept it in the fairway and made a bunch of solid 5-, 6-footers."

Mayfair birdied two of his first five holes before he stumbled to a bogey on the par-5 15th. He birdied the 18th en route to making the turn at minus-2.

The 1995 Tour Championship winner birdied the second, but followed with bogeys at three and four. Mayfair climbed back into a share of second place with birdies at the sixth and eighth.

Smith flew up the leaderboard with three birdies in a 4-hole span from the third. He parred three in a row before moving to 4-under with a birdie at the 10th. Smith wrapped bogeys at the 13th and 15th around a birdie at No. 14.

"I played really good, actually. I hit it in the bunker on the first hole, and I hit it up there real close and saved par, and then after that it was pretty easy," Smith said. "Hit it in the water on 13, made a really good bogey there, and then other than that, I was in good shape. I made a lot of birdies. I putted pretty good."

Grillo birdied the first then he traded a bogey from a birdie from the fourth. He struggled to another bogey at the 10th, but he came right back with a birdie at the 11th. The Argentine moved to minus-3 with birdies at 15 and 17.

NOTES: Hubbard's previous best position after one round was a tie for 14th at the 2014 Sanderson Farms Championship ... Duval's last made cut on the PGA Tour came last April at the Zurich Classic of New Orleans ... Defending champion Chesson Hadley opened with a 1-under 71 and he is tied for 16th ... David Toms withdrew after nine holes with a back injury, while Justin Hicks withdrew with a hip injury after carding an 81.