An outstanding left-handed pitcher and designated hitter/first baseman, Tony played in the farm system of the Chicago Cubs for three seasons. In 1988, he pitched for the Charleston Wheelers and the Winston-Salem Spirits. He played for the Peoria Chiefs in 1989 and 1990.

From 1984-87, Duenas pitched for Southern Illinois Edwardsville, where he set several school records. He was named All-American in 1985, when he helped the Cougars advance to the College World Series. That year he won 10 games and struck out 95 batters. He also hit 15 home runs, which remains a single season school record. His 13 doubles and 55 RBIs led the team that season. Duenas was inducted into the SIUE Athletics Hall of Fame in 2007.

In 1985, he pitched for Edwardsville in the Central Illinois Collegiate League. He was with the Edwardsville Traders in 1989 and 1990 and pitched for Millstadt in the Mon-Clair League in 1986, Vanzo’s in 1987, Bon-Aire in 1991 and 1992, and Granite City in 1993.

In 1987, Tony joined the Sotolar Pointers in the CYC Senior Major League, helping his team advance to the NBC Tournament in Wichita, Kansas. He pitched for Althoff High School in Belleville during the 1980s. He also coached baseball at SIU-E and then became a successful high school coach at Edwardsville, Belleville West, Springfield and Pawnee in Illinois. He is currently the head baseball coach at Richland County High School in Olney, Illinois.