Michael Putnam carded an 8-under 64 on Thursday and snared a 2-stroke lead at the Mexico Championship before play was suspended due to darkness.
The first round was halted for over an hour due to lightning in the area and later was suspended due to darkness.
Putnam, whose best finish on the Web.com Tour this season is a tie for second at the South Georgia Classic, had a pair of eagles and four birdies during his bogey-free round at El Bosque Golf Club.
Clodomiro Carranza, James Nitties, Jeff Klauk and Mathew Goggin share second after opening-round 66s, while Wes Roach, Troy Merritt, Stephan Jaeger, Nick Rousey and Manuel Merizalde are in the clubhouse at 5-under 67.
Of the handful of players who have yet to finish their opening rounds, Zack Miller and Alex Aragon are the closest to the leaders at even par through 16 and 17 holes, respectively.
Putnam, seeking his second win on the circuit and first since the 2010 Utah Championship, was spurred forward by two eagles in his first eight holes.
He played El Bosque's opening par-5 in three deft shots, then picked up six consecutive pars before eagling the next par-5, No. 8.
Momentum in hand, Putnam birdied the ninth, then turned the trick again at the 10th.
After a par on the 11th, Putnam added birdies on Nos. 12 and 17 to reach 8- under. He parred the last to hit the clubhouse with the outright lead.
NOTES: Bhavik Patel recorded a double eagle on No. 8 ... Benjamin Alvarado, second on the Web.com Tour money list, is 2-under. He can surpass money leader Edward Loar, who is not in the field this week, with a first or second-place finish ... Last year, Lee Williams posted rounds of 69-67-68-70 and won by a single stroke over Paul Haley II. Williams, who won for the first time on the Web.com Tour, is not be on hand to defend his title, as he earned his PGA Tour card for 2013 by finishing 16th on the 2012 Web.com Tour money list.