“We got grit,” said Palacios on Guatemalan players historically contending in the Championship. “We’re happy to be in such a big tournament. We rarely have a chance to compete for three majors.”

Merizalde, a reinstated amateur making his second appearance in the Championship, made seven birdies against just one bogey on Thursday morning, including three in his first four holes. The 45-year-old, ranked No. 119 in the World Amateur Golf Ranking (WAGR), finished T-29 at Grand Reserve Golf Club in Puerto Rico in 2023.

“It was beautiful,” said Merizalde on his opening round. “When you go out to the course, you never know what you'll shoot. I started with a birdie on 1, and then I was able to birdie 3 and 4, and from then on, I was just trying to get it close to the hole. I'm very happy with the low round today.”

Argentine duo Franco Ricciardelli and Mateo Pulcini finished T-4, one shot back of the leaders. Both Ricciardelli – who is making his Championship debut after getting in as an alternate – and Pulcini matched Merizalde’s single-bogey round but managed one less birdie with six apiece, including his final two holes.

“My first thought was that I was very grateful,” said Ricciardelli on entering the field as an alternate. “I came here to have fun, play some golf, and, in this case, have an opportunity on Sunday.”

Five players representing five different countries finished T-6 at four-under-par 68: Segundo Oliva Pinto of Argentina, Panama’s Omar Tejeira Jaen, Puerto Rico’s Jeronimo Esteve, Mexico’s Rodrigo Vazquez Colina and Colombia’s Jorge Andres Corchuelo Conde.

Esteve, who is making his ninth appearance, recorded the third ace in Championship history on the par-3 sixth. The 43-year-old has finished inside the top 10 in two of the last three editions of the Championship.

“It was a crazy round, started kind of weird,” said Esteve. “We got a bunch of bad breaks. My caddie reminded me that there was a lot of golf left and not to worry about it. Sure enough, we had a perfect number for the next shot, hit a good shot in there, landed short of the pin and it trickled in. That really kicked off the round.”

The 2022 LAAC champion Aaron Jarvis opened with a two-under-par 70 while Mexico’s Omar Morales, the highest-ranked player in the field at No. 12 in WAGR, carded a one-under-par 71 to sit five off the lead.