Scott Piercy and Joe Highsmith shared the clubhouse lead at the PGA Tour's Puerto Rico Open before the first round action was delayed by rain.
Play resumed after a two hour delay but bad light meant that a number of players were unable to finish their rounds.
Piercy, starting on the back nine, made an eagle on the par-4 14th, where he holed out from the fairway, but made three bogeys in his seven-under round of 65 at Grande Reserve Golf Club in Rio Grande.
He repaired the damage with birdies on his final three holes and made it into the clubhouse before the worst of the rain.
"I hit some really good shots...I played most of the hard holes pretty well," he said.
In contrast, Highsmith was bogey free for his 65.
"t was a pretty good day all around, like smooth sailing, for sure. I just stayed out of trouble all day and did a pretty good job just sticking to my process all day. Made a lot of putts early, which helps get the day going, for sure. Just kind of kept on the gas all day, so it was great," he said.
Four players were a stroke behind the leaders – Americans Brice Garnett, Erik Barnes and Kevin Streelman along with South African Garrick Higgo.
Japan's Satoshi Kodaira and Ryo Hisatune, Denmark's Rasmus Hojgaard. Scotland's Martin Laird, German Matti Schmid and local favourite Rafael Campos were all in the group a further shot back.
The tournament is played opposite this week's Arnold Palmer Invitational at Bay Hill, one of the PGA Tour's signature events designed to showcase the game's top talent.