Sergio Martínez is a retired Argentine professional boxer, born on February 21, 1975, in Avellaneda, Argentina. He is best known for his time as the middleweight champion, holding the WBC title and the WBO title during his career. Martínez is recognized for his speed, agility, and technical skills in the ring, which contributed to his success. Throughout his career, Martínez achieved notable victories against several prominent fighters, including Julio César Chávez Jr. and Paul Williams. He was named the Ring Magazine Fighter of the Year in 2010 and is considered one of the best middleweights of his era.