Mexico's Alvaro Ortiz and Ecuador's Jose Andres Miranda shared the first-round lead at 4-under 68 on Thursday in the Latin American Amateur Championship.
The winner Sunday will receive a spot in the Masters and the U.S. Amateur and British Amateur.
Ortiz, the brother of PGA Tour player Carlos Ortiz, plays at the University of Arkansas. Miranda plays at Lynn University in Florida.
Mexico's Raul Pereda de la Huerta, Puerto Rico's Erick Juan Morales and Brazil's Daniel Kenji Ishii shot 69 at Casa De Campo's Teeth of the Dog course.
Defending champion Matias Dominguez of Chile was tied for seventh after a 71. He graduated from Texas Tech last month.