Ignacio "Nacho" Beristain is a Mexico City-based boxing trainer and manager, who is considered by many to be Mexico's top trainer. He likely is most recognized today, in 2019, as having been the trainer for both of the extremely successful Marquez brothers; for the entirety of the amateur and professional career of elder brother, Juan Manuel and, except for the final few professional fights of his career, the same can be said of the younger brother, Rafael. Beristain guided and trained both of the Marquez brothers to, and through, victories in multiple world title fights, successful title defenses and championship reigns in multiple weight classes.
Beristain's first world champion was longtime Bantamweight and Super Bantamweight champion Daniel Zaragoza. Beristain also guided Gilberto Roman to the WBC Super Flyweight title. In the 1990s, Beristain handled the highly regarded Strawweight and Light Flyweight champion Ricardo Lopez.
Beristain's boxers have acquired a reputation over time, for their technical skills in the ring. However, he has been criticized by boxing writers, such as Dan Rafael and Steve Kim, for his cautious handling of the Marquez brothers, and failing to get them significant fights in recent years.