At the Diamond Belt Championship in Eureka, California, he knocked out the defending champion to win the title.

In April 1972, Álvaro won his pro debut against Herman Hampton at the Civic Auditorium in Stockton, California.

[6] The two would rematch in Carson City, Nevada less than two months later, with Álvaro stopping the bout early by knockout in the 2nd round.

Some boxing writers thought that Álvaro won the fights, though the decision victories went to the champion, Galíndez.

[10] In Álvaro's last world title attempt, he would lose to the much younger WBC Cruiserweight Champion, Carlos De León.