María Guadalupe González gave Mexico its twelfth gold medal in the Pan-American Games, with her victory on the 20 kilometers march.
She imposed herself since the start and never allowed her rivals to get even close.
With just two years and a half in this sport, she imposed a new record of 1:29.24 hours.
The silver went to Brazilian Erika Decena and bronze for Ecuadorean Paola Pérez.
González had to be taken to the hospital because she fell after crossing the finish line due to dehydration.
The male 20 kilometers will be held later in the evening, with Mexican Eder Sánchez as the favorite.