Eight birdies saw Rafael Campos shoot an opening-round 64 to take a one-shot lead at the Puerto Rico Open on Thursday.
Campos - playing in front of his home fans - sits just ahead of George McNeill after the first day's play at Coco Beach, while defending champion Alex Cejka is two back in a four-way tie for third.
After picking up shots at three of the first six holes, Campos continued his charge towards the summit with four birdies in a row from the ninth.
He added another at the par-five 15th before parring the final three to end the day eight under.
McNeill, who started at the 10th, would have been level with the Puerto Rican had he not bogeyed his final hole, the 40-year-old carding a five at the ninth to see him drop a shot back.
Prior to that slip-up, McNeill had birdied six out of seven holes from the second.
Cejka is well-placed going into Friday's second round thanks to seven birdies, a bogey at the 13th the only mishap at the start of his title defence.
The German is joined on six under by Aaron Baddeley, Frank Lickliter II and Will MacKenzie, while Englishman Luke Donald is three under after a 69.